UPBGE is very active - a fork of bge with enchanced phyiscs, rendering, and workflow additions. enchanced mesh editing w/ BVH_Tree_From_KX_MeshProxy() https://github.com/UPBGE
Setting the light in the Unreal Engine 4.20 is quite good, with many different types of lighting duck life
Stylish Water Shader 2.0 for Unity with many great features, I enjoyed this new application run 3
Michael Dunnam has tons of useful stuff for game developers on his Gumroad page. For example, look at these free shiny IMM brushes: 17 Accurate gemstone IMMs, all wrapped up in one convenient insert multimesh brush.
You can also check out his other IMM brushes. Here are some of the sets: