A lot of mods add new techs or change existing ones. Endless Moons comes to mind, that's always a fun one. As for modules, I haven't seen a lot in terms of adding new weapon modules or things like that. Most of the time, the mods out there change what modules do or what kind of ships can equip them. I think there's one out there that lets you equip the economic/scientific behemoth modules onto civilian ships, and then of course you also have the balancing mods that usually make projectile weapons stronger.

RoboPig wrote:

Endless Moons comes to mind, that's always a fun one. 

I combine Endless Moons mod with More Anomalies Mod, what is amazing -> More Anomalies