Kaitei no Boukun

All shorts found on the Japanese Classics Collection box set, curated by Digital Meme, a Japanese company dedicated to obscure East Asian media.

Entries date between 1928 and 1950, making these some of the oldest available anime.

Not listed:
Doubutsu Sumo Taikai (Animal Sumo) https://myanimelist.net/anime/5812/Doubutsu_Sumo_Taikai?q=animal%20sumo&cat=anime
Ohisama to Kaeru (The Sun and the Frogs) https://myanimelist.net/anime/6828/Ohi-sama_to_Kaeru?q=the%20sun%20and%20the%20frogs&cat=anime
Ahiru no Otegara (The Duckling Saves the Day)

These three were only omitted because there wasn't enough room on the list, and it didn't feel worth it to make a part 2. In Ahiru no Otegara's case, this anime is not in the MAL database.