So, there are projects like these;
https://github.com/ihhub/fheroes2
Projects that in one way or another aim to modernize a classic, or try make it more playable on modern machine, or just try to expand on things (like gzdoom does)
what other projects are out there in a similar vein?
I find this a little difficult to search for, even with specific terms (i tried finding myself)
You can find them at openra.net
They have reimplementation of Command & Conquer, Red Alert and Dune 2000. Excellent work really.