As per title. I personally really enjoy deckbuilding / engine builders and civilisation games, but most of them understandably end just as you’re hitting the sweet spot of getting your engine up and running. Probably why Through the Ages is my favorite game - has all the mechanics I like, but lasts long enough that I feel like I get a chance to run them.
I recommend checking out Arboretum: https://youtu.be/mmiXSOG1BtQ
It’s a small box game (just a deck of cards) so not too expensive, and it really hits that “If I discard this someone else is going to want it.”