Mostly Instagram is quite evil — specially its “isolation algorithm”… but luckily Instagram also has its corners where interesting content can be found. For example, the works of past masters:
One perfect frame (@one.perfect.frame) — “frames/scenes from classic American cartoons”
Manga masters (@mastersofmanga) — “A tribute to the Gods”
Looney Tunes Backgrounds (@looneytunesbackground) — Looney Tunes without Looney Tunes