Funny you would say this I just got done watching all of Avatar the Last Airbender and it is great.
The characters are so easy to gravitate towards and love.
Personally, I do not have much interests in the Legend of Korra but I will give it a go after your recommendation.
Also, this one is an obvious choice; Rick and Morty is easily one of my favorite cartoons to come out created by
some of my role models, Justin Roiland, and Dan Harmon.