A lot of good stuff already covered but missing a few:
Batman: The Brave and Bold - More of the Bright Knight than Dark Knight. Wonderful if you're into poking fun at the various stuff for super heroes.
Chowder - A kid with a bottomless stomach and a love of eating is a trainee chef for the master chef Mung Daal. Various wacky adventures ensue.
Helluva Boss - New YT series, only four eps so far but have been enjoying the antics of Blitzo (the o is silent) who runs a demonic assassination business and his crew. Has a slight Invader Zim tinge to it (not helped by Richard Steven Horvitz voicing Moxxie)
Samurai Jack - (To go with Primal listed above) - Genndy Tartakovsky doing his stuff as always.
The Amazing Wold of Gumball - A blue cartoon cat and his adopted fish brother go on adventures and get into trouble. Can just be downright hilarious, the mixing of the various animation styles for the different chars and how they play with that is great on top of just how fun it is.
Megas XLR - Giant robot falls through time and gets found and modified so that only Coop has any idea how to pilot it any more. Everything can be solved by punching.
Young Justice - Follows the side-kicks and young heroes as they fight to prove themselves to the Justice League.
Venture Brothers - Cruelly cut down in its prime. Follow the life and times of, now grown, child adventurer Rusty Venture, his body guard Brock and his two sons Dean and Hank as he tries to live up to his fathers legacy. First season is a bit iffy for some but once you get to thelast few eps and then S2 it really start to take off.
We Bare Bears - Three bears try to make a home for themselves in the human world (not a massive fan of the Baby Bear eps but ymmv). Just a cute fun show.
And would also second some that haven't got the same attention as others yet:
DuckTales - A great re-imagining of the original show and manages to flesh out just about every character within the series. Just recently finished its run (should've got more).
Wander Over Yonder - Wander roams the universe with is trusty steed Sylvia foiling the machinations of Lord Hater. Just a fun time all round really.