Kickstarted game most pleased you backed
I’m going to assume that this should be a game that has actually been delivered, and I’ll add the condition that it’s something I’ve actually played.
Kingdom by Ben Robbins would get my nod. A wonderfully tight game that can run in a single session (if you want to). I played and facilitated the heck out of this at Forge Midwest in 2014 and loved every minute of it.
Tenra Bansho Zero would be a close runner-up.