Various freeware LISP tools for AutoCAD:
MAZE.LSP - random maze generator for AutoCAD, converted from CLISP
TotalLayouts.LSP - automatic reactor creating a field variable with the current number of DWG-layouts (autoload this)
COG3D.LSP - display center of gravity point for solids and regions
CenOf.LSP - display XY(Z) or osnap center of selected object(s)
CMDtimer.LSP - reactor-based timing of AutoCAD commands - track execution time of native commands
Txt2Ref.LSP - replaces drawing texts with block references of the same name
More freeware tools available on https://www.cadstudio.cz/freeware and on https://www.cadforum.cz (and follow CAD Studio on Facebook - @CADstudio)