What are some good short-form episodic anime series? (Usually less than 10 minutes per episode)

Nichijou has 25 20 minute long episodes, but they're broken into sections between 5-15 minutes. You could watch half an episode at a time if you wanted.

It's a slice of life comedy by Kyoani, with some incredibly high production quality. Highly recommend you try watching the first episode to see if you like it.

Episodic Anime shows that are short in length?

Why, Hetalia of course!

Hetalia is an anime where it basically parodies countries and geopolitics alike. Plus, it’s one of those shows where the English dub prevails.

Wakako Zake if you're into food/slice-of-life. I think each episode is 2 min 30 seconds with 12 episodes total. So you could watch the entire run in the amount of time it'd take to watch a full episode of something else.

Senyuu - incredibly funny, and episode is only ~3 or 4 minutes. I guess I’d describe it as a parody of adventure anime.

Edit: I guess I'll add Pop Team Epic... sorta. The episodes are ~20 minutes long, but it's partly split into sections (like Nichijou). The reason I only "sorta" recommend it is that you probably want to watch the episodes in full. I don't wanna spoil anything (this is the kinda show where you want to go in knowing absolutely nothing), so that's all I'll say.

Tonari no Seki-Kun is a really fun shortform series. Centers around a kid named Seki who goofs off during class in increasingly elaborate and ridiculous ways and how he distracts the girl next to him who tries her darndest to focus on class, but gets almost as caught up in it as him. Each episode lasts about 15 minutes and they're pretty fun to watch!

Tonkatsu DJ Agetarou (10 min each)

It's about this boy who aspires to be a DJ and through pursuing that goal he finds parallels with his father's work making tonkatsu. Lots of fun, has really good music, and is pretty sweet on top of that.

I liked Karen Senki but it seems to have really low ratings haha. ~11 minutes per episode

For simple time-fillers, I really liked Robo to Shoujo (Kari) for something with a semblance of a plot, Yurumates for your typical yonkoma adaptaion and AIURA for something a bit more relaxed.

If you want some political humor (dareisay from a simpler time) and have at least a passing familiarity with mahjong, then the three shorts released for The Legend of Koizumi are also a pretty fun ride.

Bananya. It's about cats who live in bananas. It's mostly for kids, but it's super cute and has the VA for Eren from AOT voicing most of the cast.

Aggretsuko on Netflix, a show from the makers of Hello Kitty about when one of their mascot characters takes an office job and gets her soul ground down to a fine powder, and her only escape is death metal karoke. There were original one minute shorts that you can find floating around on YouTube, but they struck a deal with Netflix to make ten 10 minute episodes that are far more serialized.

I'm surprised nobody has mentioned Space Patrol Luluco, which is done by one of the lead animators who also did Little Witch Academia :)
https://en.wikipedia.org/wiki/Space_Patrol_Luluco

Someone else also mentioned Nichijou, which I think would be a good fit. Each episode is about 25m long, but it's composed of a number of shorts, so it's not too hard to stop after a couple and do something else, and then return.