diff --git a/setup.cfg b/setup.cfg
index 9d28525..1099619 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -46,15 +46,12 @@ not_skip =
 [flake8]
 exclude =
     bootstrap.py,
-    src/RestrictedPython/tests,
+
 
 ignore =
-    N801,
-    N802,
-    N803,
-    N805,
-    N806,
-    N812,
+
+
+no-accept-encodings = True
 
 [coverage:run]
 branch = True
diff --git a/tox.ini b/tox.ini
index d3a2528..fd0ce6c 100644
--- a/tox.ini
+++ b/tox.ini
@@ -94,13 +94,29 @@ skip_install = true
 
 deps =
     -cconstraints.txt
+    isort
     flake8
     # helper to generate HTML reports:
     flake8-html
     # Useful flake8 plugins that are Python and Plone specific:
+    flake8-coding
     flake8-debugger
+    flake8-deprecated
+    flake8-print
+    flake8-pytest
     flake8-todo
-    isort
+    flake8-isort
+    mccabe
+    # Potential flake8 plugins that should be used:  # TBD
+    #flake8-blind-except
+    #flake8-commas
+    #flake8-docstrings
+    #flake8-mypy
+    #flake8-pep3101
+    #flake8-plone-hasattr
+    #flake8-string-format
+    #flake8_strict
+    #flake8-quotes
 
 commands =
     mkdir -p {toxinidir}/reports/flake8