VTube-LASER - Recommended STL File Editor - MeshLab (Free)

The MeshLab editor allows you to decimate (reduce the point count) for very dense STL files.  It's our favorite because it is easy and works great.

https://sourceforge.net/projects/meshlab/

(Note: This is a free software package. Users often complain about this program's issues. But we only use it for one purpose. It works great for our decimation application.)