I could sit down and marathon Steven Universe all day long! I mean, I don't, because I'm caught up on the series, I don't have that kind of time, and I don't want to make myself cry for that long. But the quality is so high up there.
I'm like 11 episodes in to Gravity Falls. If I get a moment to breath this winter, I can easily see myself just curling up with some hot chocolate and catching up on that.
Otherwise, the main cartoon from my childhood that I could binge watch is Animaniacs. Maybe a few others, like Tiny Toons, but I have a hard time thinking of anything other than Animaniacs o.O.