Maihime

Featuring little to no dialogue and/or characters and the experience is carried by the music and/or visual atmosphere.

Part 1 - https://myanimelist.net/stacks/311
Part 2 - https://myanimelist.net/stacks/5128
Part 3 - https://myanimelist.net/stacks/8036
Part 4 - https://myanimelist.net/stacks/8173
Part 5 - https://myanimelist.net/stacks/9135
Part 6 - https://myanimelist.net/stacks/9240
Part 7 - https://myanimelist.net/stacks/9448
Part 8 - https://myanimelist.net/stacks/9461
Part 9 - https://myanimelist.net/stacks/20874
Part 10 - https://myanimelist.net/stacks/60874

画ニメ (Ga-nime) A series of experimental artistic films produced by Toei Animation in 2004-2007.

Note: The inclusion of Kono Shihai kara no Sotsugyou: Ozaki Yutaka to this list is based on the information on the now defunct page of the Toei website which lists it as Ga-nime unlike many other subsequent releases or collections.

http://corp.toei-anim.co.jp/english/film/ganime_yutaka_ozaki.php

This list includes very unique and artsy anime that are around one episode in length, so anything between 20 to 50 minutes. So movies and really short stuff are excluded. Also compilations of multiple unrelated anime (ex: Genius Party) would also be here is each episode is in that timeframe.

Anime series that covers all of the original source they're based on, with some notes.

Check out the other parts at this link:
https://myanimelist.net/profile/Yuriko_Sakai/stacks
The Stacks are updated constantly so check them every once in a while :)

A big "thank you" to my friend Lorissagg for helping me with some researches :D
Here's his profile if you're interested: https://myanimelist.net/profile/Lorissagg