diff --git a/cscs-checks/apps/amber/amber_check.py b/cscs-checks/apps/amber/amber_check.py
index 4018e923ce..8594d30394 100644
--- a/cscs-checks/apps/amber/amber_check.py
+++ b/cscs-checks/apps/amber/amber_check.py
@@ -38,7 +38,7 @@ def __init__(self, input_file, output_file):
                                      output_file, 'perf', float, item=1)
         }
         self.maintainers = ['SO', 'VH']
-        self.tags = {'scs'}
+        self.tags = {'scs', 'external-resources'}
 
 
 @rfm.required_version('>=2.16')
diff --git a/cscs-checks/apps/espresso/espresso_check.py b/cscs-checks/apps/espresso/espresso_check.py
index 4cacf2934f..c21c900f65 100644
--- a/cscs-checks/apps/espresso/espresso_check.py
+++ b/cscs-checks/apps/espresso/espresso_check.py
@@ -11,7 +11,7 @@ def __init__(self, scale):
         super().__init__()
         self.descr = 'Quantum Espresso CPU check'
         self.maintainers = ['AK', 'LM']
-        self.tags = {'scs', 'production'}
+        self.tags = {'scs', 'production', 'external-resources'}
         self.sourcesdir = os.path.join(self.current_system.resourcesdir,
                                        'Espresso')
 
diff --git a/cscs-checks/apps/gromacs/gromacs_check.py b/cscs-checks/apps/gromacs/gromacs_check.py
index 05f776383c..213db9531c 100644
--- a/cscs-checks/apps/gromacs/gromacs_check.py
+++ b/cscs-checks/apps/gromacs/gromacs_check.py
@@ -41,7 +41,7 @@ def __init__(self, output_file):
                 'num_switches': 1
             }
         }
-        self.tags = {'scs'}
+        self.tags = {'scs', 'external-resources'}
 
 
 @rfm.required_version('>=2.19')
diff --git a/cscs-checks/apps/icon/rrtmgp_check.py b/cscs-checks/apps/icon/rrtmgp_check.py
index 69a48430d9..e6e332c674 100644
--- a/cscs-checks/apps/icon/rrtmgp_check.py
+++ b/cscs-checks/apps/icon/rrtmgp_check.py
@@ -14,6 +14,7 @@ def __init__(self):
         self.valid_prog_environs = ['PrgEnv-pgi']
         self.sourcesdir = os.path.join(self.current_system.resourcesdir,
                                        'RRTMGP')
+        self.tags = {'external-resources'}
         self.prebuild_cmd = ['cp build/Makefile.conf.dom build/Makefile.conf']
         self.executable = 'python'
         self.executable_opts = [
diff --git a/cscs-checks/apps/lammps/lammps_check.py b/cscs-checks/apps/lammps/lammps_check.py
index 5321767f08..017dd0b067 100644
--- a/cscs-checks/apps/lammps/lammps_check.py
+++ b/cscs-checks/apps/lammps/lammps_check.py
@@ -33,7 +33,7 @@ def __init__(self):
             }
         }
 
-        self.tags = {'scs'}
+        self.tags = {'scs', 'external-resources'}
         self.maintainers = ['TR', 'VH']
 
 
diff --git a/cscs-checks/apps/namd/namd_check.py b/cscs-checks/apps/namd/namd_check.py
index 2a75ac0efd..31b3095c5c 100644
--- a/cscs-checks/apps/namd/namd_check.py
+++ b/cscs-checks/apps/namd/namd_check.py
@@ -44,7 +44,7 @@ def __init__(self, arch, scale, variant):
         }
 
         self.maintainers = ['CB', 'LM']
-        self.tags = {'scs'}
+        self.tags = {'scs', 'external-resources'}
         self.strict_check = False
         self.extra_resources = {
             'switches': {
diff --git a/cscs-checks/apps/openfoam/check_openfoam.py b/cscs-checks/apps/openfoam/check_openfoam.py
index ade32256d7..48dd58b4ba 100644
--- a/cscs-checks/apps/openfoam/check_openfoam.py
+++ b/cscs-checks/apps/openfoam/check_openfoam.py
@@ -22,7 +22,7 @@ def __init__(self):
         self.num_cpus_per_task  = 1
 
         self.maintainers = ['MKr']
-        self.tags = {'scs', 'production'}
+        self.tags = {'scs', 'production', 'external-resources'}
 
         self.pre_run = ['source $FOAM_BASH']
 
diff --git a/cscs-checks/apps/openfoam/check_openfoam_extend.py b/cscs-checks/apps/openfoam/check_openfoam_extend.py
index 68a9a440de..9ec5285f6d 100644
--- a/cscs-checks/apps/openfoam/check_openfoam_extend.py
+++ b/cscs-checks/apps/openfoam/check_openfoam_extend.py
@@ -28,7 +28,7 @@ def __init__(self):
                 r'Finalising parallel run', self.stdout)
 
         self.maintainers = ['MKr']
-        self.tags = {'scs', 'production'}
+        self.tags = {'scs', 'production', 'external-resources'}
         self.pre_run = ['source $FOAM_INST_DIR/foam-extend-4.0/etc/bashrc']
 
 
diff --git a/cscs-checks/cuda/cuda_checks.py b/cscs-checks/cuda/cuda_checks.py
index bd59b813e2..a2669b7ad2 100644
--- a/cscs-checks/cuda/cuda_checks.py
+++ b/cscs-checks/cuda/cuda_checks.py
@@ -27,7 +27,7 @@ def __init__(self):
             self.nvidia_sm = '37'
 
         self.maintainers = ['AJ', 'VK']
-        self.tags = {'production', 'craype'}
+        self.tags = {'production', 'craype', 'external-resources'}
 
 
 @rfm.required_version('>=2.14')
diff --git a/cscs-checks/cuda/multi_gpu.py b/cscs-checks/cuda/multi_gpu.py
index a61efc3a23..76c5eb385e 100644
--- a/cscs-checks/cuda/multi_gpu.py
+++ b/cscs-checks/cuda/multi_gpu.py
@@ -61,7 +61,7 @@ def __init__(self):
             'kesch:cn:d2h':   (7584, -0.1, None, 'MB/s'),
             'kesch:cn:d2d': (137408, -0.1, None, 'MB/s')
         }
-        self.tags = {'diagnostic', 'mch', 'craype'}
+        self.tags = {'diagnostic', 'mch', 'craype', 'external-resources'}
         self.maintainers = ['AJ', 'VK']
 
     def _xfer_pattern(self, xfer_kind, devno, nodename):
diff --git a/cscs-checks/cuda/nvml_check.py b/cscs-checks/cuda/nvml_check.py
index 51b1127155..7ddc1f8e0f 100644
--- a/cscs-checks/cuda/nvml_check.py
+++ b/cscs-checks/cuda/nvml_check.py
@@ -19,6 +19,7 @@ class NvmlCheck(rfm.RegressionTest):
     NVML_GOM_LOW_DP Designed for running graphics applications that do not
                     require < high bandwidth double precision.
     '''
+
     def __init__(self):
         super().__init__()
         self.descr = 'check GPU compute mode'
@@ -37,4 +38,4 @@ def __init__(self):
             self.stdout)
 
         self.maintainers = ['AJ', 'VK']
-        self.tags = {'production', 'craype'}
+        self.tags = {'production', 'craype', 'external-resources'}
diff --git a/cscs-checks/libraries/io/netcdf_compile_run.py b/cscs-checks/libraries/io/netcdf_compile_run.py
index 2257e5aa39..3f3b2a084e 100644
--- a/cscs-checks/libraries/io/netcdf_compile_run.py
+++ b/cscs-checks/libraries/io/netcdf_compile_run.py
@@ -40,7 +40,7 @@ def __init__(self, lang, linkage):
         self.num_tasks_per_node = 1
         self.sanity_patterns = sn.assert_found(r'SUCCESS', self.stdout)
         self.maintainers = ['AJ', 'VK']
-        self.tags = {'production', 'craype'}
+        self.tags = {'production', 'craype', 'external-resources'}
 
     def setup(self, partition, environ, **job_opts):
         if self.current_system.name == 'kesch':
diff --git a/cscs-checks/libraries/math/scalapack_compile_run.py b/cscs-checks/libraries/math/scalapack_compile_run.py
index 9a9bfbe886..624b1a9770 100644
--- a/cscs-checks/libraries/math/scalapack_compile_run.py
+++ b/cscs-checks/libraries/math/scalapack_compile_run.py
@@ -27,7 +27,7 @@ def __init__(self, linkage):
         self.build_system = 'SingleSource'
         self.build_system.fflags = ['-O3']
         self.maintainers = ['CB', 'LM', 'MKr']
-        self.tags = {'production'}
+        self.tags = {'production', 'external-resources'}
 
 
 @rfm.required_version('>=2.14')
@@ -66,33 +66,3 @@ def scalapack_sanity(number1, number2, expected_value):
             scalapack_sanity(4, 3, 0.2483911184660867),
             scalapack_sanity(4, 4, 0.1701907253504270)
         ])
-
-
-# FIXME: This test is obsolete; it is kept only for reference.
-# NOTE:  The test case is very small, but larger cases did not succeed!
-@rfm.required_version('>=2.14')
-@rfm.parameterized_test(['dynamic'])
-class ScaLAPACKPerf(ScaLAPACKTest):
-    def __init__(self, linkage):
-        super().__init__(linkage)
-
-        self.tags |= {'monch_acceptance'}
-        self.sourcepath = 'scalapack_performance_compile_run.f'
-        self.valid_systems = ['monch:compute']
-        self.valid_prog_environs = ['PrgEnv-gnu']
-        self.num_tasks = 64
-        self.num_tasks_per_node = 16
-
-        self.sanity_patterns = sn.assert_found(r'Run', self.stdout)
-        self.perf_patterns = {
-            'perf': sn.max(
-                sn.extractall(r'GFLOPS/s:\s+(?P<gflops>\S+)',
-                              self.stdout, 'gflops', float)
-            )
-        }
-
-        self.reference = {
-            'monch:compute': {
-                'perf': (24., -0.1, None)
-            }
-        }
diff --git a/cscs-checks/mch/fieldextra_check.py b/cscs-checks/mch/fieldextra_check.py
index b45acd15d6..60129d7887 100644
--- a/cscs-checks/mch/fieldextra_check.py
+++ b/cscs-checks/mch/fieldextra_check.py
@@ -8,7 +8,7 @@ class FieldextraTestBase(rfm.RunOnlyRegressionTest):
     def __init__(self):
         super().__init__()
         self.maintainers = ['MKr']
-        self.tags = {'mch'}
+        self.tags = {'mch', 'external-resources'}
 
         self.valid_systems = ['kesch:cn']
         self.valid_prog_environs = ['PrgEnv-gnu-nompi']
diff --git a/cscs-checks/microbenchmarks/hpcg/hpcg_benchmark.py b/cscs-checks/microbenchmarks/hpcg/hpcg_benchmark.py
index 0f4207aae3..6771c96987 100644
--- a/cscs-checks/microbenchmarks/hpcg/hpcg_benchmark.py
+++ b/cscs-checks/microbenchmarks/hpcg/hpcg_benchmark.py
@@ -52,7 +52,7 @@ def __init__(self):
         }
 
         self.maintainers = ['SK']
-        self.tags = {'diagnostic', 'benchmark', 'craype'}
+        self.tags = {'diagnostic', 'benchmark', 'craype', 'external-resources'}
 
     @property
     @sn.sanity_function
diff --git a/cscs-checks/microbenchmarks/spec-accel/spec.py b/cscs-checks/microbenchmarks/spec-accel/spec.py
index 2fa4f68edd..e6cac960bd 100644
--- a/cscs-checks/microbenchmarks/spec-accel/spec.py
+++ b/cscs-checks/microbenchmarks/spec-accel/spec.py
@@ -53,7 +53,7 @@ def __init__(self, prg_envs):
         }
 
         self.maintainers = ['SK']
-        self.tags = {'diagnostic'}
+        self.tags = {'diagnostic', 'external-resources'}
 
     def setup(self, partition, environ, **job_opts):
         self.pre_run = ['source ./shrc', 'mv %s config' %
diff --git a/cscs-checks/system/io/ior_check.py b/cscs-checks/system/io/ior_check.py
index a26b6e97c5..874113b61e 100644
--- a/cscs-checks/system/io/ior_check.py
+++ b/cscs-checks/system/io/ior_check.py
@@ -108,7 +108,7 @@ def __init__(self, base_dir):
 
         systems_to_test = ['dom', 'daint']
         if self.current_system.name in systems_to_test:
-            self.tags |= {'production'}
+            self.tags |= {'production', 'external-resources'}
 
     def setup(self, partition, environ, **job_opts):
         super().setup(partition, environ, **job_opts)
diff --git a/cscs-checks/tools/io/cdo.py b/cscs-checks/tools/io/cdo.py
index a002df9bce..62e659ee05 100644
--- a/cscs-checks/tools/io/cdo.py
+++ b/cscs-checks/tools/io/cdo.py
@@ -40,7 +40,7 @@ def __init__(self):
             self.modules = ['CDO']
 
         self.maintainers = ['SO']
-        self.tags = {'production', 'mch'}
+        self.tags = {'production', 'mch', 'external-resources'}
 
 
 # Check that the netCDF loaded by the CDO module supports the nc4 filetype
diff --git a/cscs-checks/tools/io/nco.py b/cscs-checks/tools/io/nco.py
index 504ebe928c..8a6a3f2e98 100644
--- a/cscs-checks/tools/io/nco.py
+++ b/cscs-checks/tools/io/nco.py
@@ -33,7 +33,7 @@ def __init__(self):
             self.modules = ['NCO']
 
         self.maintainers = ['SO']
-        self.tags = {'production', 'mch'}
+        self.tags = {'production', 'mch', 'external-resources'}
 
 
 # Check that the netCDF loaded by the NCO module supports the nc4 filetype
diff --git a/cscs-checks/tools/profiling_and_debugging/berkeley-ert-nvprof.py b/cscs-checks/tools/profiling_and_debugging/berkeley-ert-nvprof.py
index bc3d9ba36b..7bfc7c64fa 100644
--- a/cscs-checks/tools/profiling_and_debugging/berkeley-ert-nvprof.py
+++ b/cscs-checks/tools/profiling_and_debugging/berkeley-ert-nvprof.py
@@ -72,7 +72,7 @@ def __init__(self, gpudims, flop, repeat):
         ]
         self.build_system.ldflags = ['-O3']
         self.maintainers = ['JG']
-        self.tags = {'scs'}
+        self.tags = {'scs', 'external-resources'}
         gpu_blocks, gpu_threads = gpudims
         self.name = 'ertgpu_Run.{}_FLOPS.{}_GPUBlocks.{}_GPUThreads.{}'.format(
             repeat, flop, gpu_blocks, gpu_threads)
diff --git a/cscs-checks/tools/profiling_and_debugging/berkeley-ert.py b/cscs-checks/tools/profiling_and_debugging/berkeley-ert.py
index 505905d0f9..e9cef9be20 100644
--- a/cscs-checks/tools/profiling_and_debugging/berkeley-ert.py
+++ b/cscs-checks/tools/profiling_and_debugging/berkeley-ert.py
@@ -23,7 +23,7 @@ def __init__(self):
                                        'roofline', 'ert')
         self.rpt = '%s.rpt' % self.executable
         self.maintainers = ['JG']
-        self.tags = {'scs'}
+        self.tags = {'scs', 'external-resources'}
 
     def setup(self, partition, environ, **job_opts):
         super().setup(partition, environ, **job_opts)
diff --git a/cscs-checks/tools/profiling_and_debugging/intel_advisor_roofline.py b/cscs-checks/tools/profiling_and_debugging/intel_advisor_roofline.py
index 977f2c2ab2..6c260b9e74 100644
--- a/cscs-checks/tools/profiling_and_debugging/intel_advisor_roofline.py
+++ b/cscs-checks/tools/profiling_and_debugging/intel_advisor_roofline.py
@@ -238,7 +238,7 @@ def __init__(self, repeat, toolversion, datalayout):
         }
 
         self.maintainers = ['JG']
-        self.tags = {'production'}
+        self.tags = {'production', 'external-resources'}
 
     def setup(self, partition, environ, **job_opts):
         super().setup(partition, environ, **job_opts)
diff --git a/cscs-checks/tools/profiling_and_debugging/intel_sde_berkeley_stream.py b/cscs-checks/tools/profiling_and_debugging/intel_sde_berkeley_stream.py
index 0c410e43ad..b3ff46d5b4 100644
--- a/cscs-checks/tools/profiling_and_debugging/intel_sde_berkeley_stream.py
+++ b/cscs-checks/tools/profiling_and_debugging/intel_sde_berkeley_stream.py
@@ -35,7 +35,7 @@ def __init__(self):
         self.sanity_patterns = sn.assert_found('Total FLOPs =', self.rpt)
         self.post_run = ['SDE/parse-sde.sh %s.* &> %s' % (self.sde, self.rpt)]
         self.maintainers = ['JG']
-        self.tags = {'scs'}
+        self.tags = {'scs', 'external-resources'}
 
     @property
     @sn.sanity_function
diff --git a/cscs-checks/tools/profiling_and_debugging/intel_sde_roofline.py b/cscs-checks/tools/profiling_and_debugging/intel_sde_roofline.py
index f31cb542f7..ab98a6cefb 100644
--- a/cscs-checks/tools/profiling_and_debugging/intel_sde_roofline.py
+++ b/cscs-checks/tools/profiling_and_debugging/intel_sde_roofline.py
@@ -68,7 +68,7 @@ def __init__(self, repeat, toolsversion, datalayout):
         self.sanity_patterns = sn.assert_found('Total FLOPs =', self.rpt)
         self.post_run = ['SDE/parse-sde.sh %s.* &> %s' % (self.sde, self.rpt)]
         self.maintainers = ['JG']
-        self.tags = {'scs'}
+        self.tags = {'scs', 'external-resources'}
         self.sanity_patterns = sn.all([
             sn.assert_eq(sn.extractsingle(
                 r'^Intel\(R\) Software Development Emulator\.  Version:  '
diff --git a/cscs-checks/tools/profiling_and_debugging/intel_vtune_roofline.py b/cscs-checks/tools/profiling_and_debugging/intel_vtune_roofline.py
index 0ae40b9f51..ad745a924b 100644
--- a/cscs-checks/tools/profiling_and_debugging/intel_vtune_roofline.py
+++ b/cscs-checks/tools/profiling_and_debugging/intel_vtune_roofline.py
@@ -76,7 +76,7 @@ def __init__(self, repeat, toolsversion, datalayout):
         # NOTE: -allow-multiple-runs requires to install vtune drivers
         # TODO: -collect memory-access
         self.maintainers = ['JG']
-        self.tags = {'scs'}
+        self.tags = {'scs', 'external-resources'}
         self.sanity_patterns = sn.all([
             sn.assert_found('loop complete.', self.stdout),
             sn.assert_eq(sn.extractsingle(