ik I am a bit late in answering but here goes nothing
I use unity as my game engine (some time ago when I made games still do but lately didnt get much time)
But yeah I use unity and unity's asset store mainly since I didnt learn blender yet to make my own models, and as for 2D games i use simple shapes given default by the unity's editor (because why not) and apparently use the color scheme to give simple colors etc
So yeah unity and visual studio (an ide to write c# for unity's code to work) is what I use for game dev