Suisei

Includes regular anime series, movies, experimental shorts, and even music videos. Anything that can be considered unique in either its art style or method of animation. Probably not every entry in this list will be suited to one's taste, but as we all know, art is subjective.

Also, I've tried to limit the entries to one per style.

Works that aren't here on MAL:
- Our House, by Murata Caori

This is a compilation of Avante-Garde shorts that are unique, mind-blowing and addicting. These will give you a different POV on the world of animation.
Includes short films, short series, commercials, station IDs, and specials.

Part 1: https://myanimelist.net/stacks/23559
Part 2: https://myanimelist.net/stacks/23560
Part 3: https://myanimelist.net/stacks/23563
Part 4: https://myanimelist.net/stacks/23564
Part 5: https://myanimelist.net/stacks/23566
Part 6: https://myanimelist.net/stacks/23567
Part 7: https://myanimelist.net/stacks/23568
Part 8: https://myanimelist.net/stacks/23569
Part 9: https://myanimelist.net/stacks/23571
Part 10: https://myanimelist.net/stacks/23573
Part 11: https://myanimelist.net/stacks/23575

https://en.wikipedia.org/wiki/Paint-on-glass_animation

There are short-length anime series of OVAs, specials, ONAs, and music-centered anime that offer unique and captivating experiences in a more compact format. Here are some recommendations of short-length anime:

These stacks are meant for cataloguing every stop-motion animation on Myanimelist. The list is the result of research by the Stop-Motion Animation Appreciation Society:

https://myanimelist.net/clubs.php?cid=16200

Stop-motion is a form of animation in which objects are manipulated little by little while each frame is shot separately. Puppet animation is the most common, but before 1935 cutout animation was also very common. Among other types are claymation, pixilation (now removed from the database), object and model animation. In this list also works using sand, charcoal or paint are included, since in the form they've been accepted to MAL, they also include gradual manipulation and shot by shot filming.

Part 1: https://myanimelist.net/stacks/47018
Part 2: https://myanimelist.net/stacks/47020
Part 3: https://myanimelist.net/stacks/47021
Part 4: https://myanimelist.net/stacks/47022
Part 5: https://myanimelist.net/stacks/47023
Part 6: https://myanimelist.net/stacks/47026
Part 7: https://myanimelist.net/stacks/47027
Part 8: https://myanimelist.net/stacks/47032
Part 9: https://myanimelist.net/stacks/47034

Part 11: https://myanimelist.net/stacks/47036
Part 12: https://myanimelist.net/stacks/47038
Part 13: https://myanimelist.net/stacks/49186
Part 14: https://myanimelist.net/stacks/51880

The Stop-Motion Animation Appreciation Society club: https://myanimelist.net/clubs.php?cid=16200
Art house, avant-garde and experimental club: https://myanimelist.net/clubs.php?cid=74845

The list also contains works by Takashi Itou which might rather be classified as still motion.

Part 2: https://myanimelist.net/stacks/51626