Pixologic Zbrush Core — Mini

This is the secret sauce. In other free software, you have to manually add polyons to sculpt detail. In Core Mini, the software automatically adds polygons (subdivides) exactly where you are sculpting. You never have to think about "poly count" until you hit a warning limit.

Note: The inability to export high-resolution ZTL files to the full ZBrush is a major limitation, but exporting OBJ works perfectly for sending models to Blender, Unity, or Unreal Engine. pixologic zbrush core mini

To be fair to Pixologic, they have to sell the full ZBrush and the $179 ZBrushCore. Therefore, ZBrush Core Mini has significant guardrails. This is the secret sauce