Games

The only must haves are QoL stuff like repricing up weapons, run and gun, jobs menu reworks etc.

Everything else is what flavour you want, Neolithic colony, wh40k gene editing , etc

Everyone plays a bit different, personally I'd recommend playing the vanilla game for a bit and using mods to flesh things out or iron out any rough edges in how you experience the game. The modding scene for the game is absolutely phenomenal, if at any point you're going "gee, there's got to be a better way to do X, deal with Y, or add more Z", there's probably a mod that does it, for example I like designing my colony fairly early on (so I have something to build towards), but since the existing mono-color plan gets confusing pretty fast (what was wall and what was workbench, tool cabinet, light, etc), I find More Planning to be a bit of a must have. As a blanket statement, the Vanilla Expanded mods are very well done and integrate neatly into the game (that said, they aren't necessary meant to all be run at once, so you can pick and choose what you want and go from there).

I have a pretty decent list going, but if we're just talking a short list of personal favorites, I really love Megafauna, Frozen Snow Fox's Bionics, and Cyber Fauna. (Oh and a shameless self-plug for my own mods)