Anything you've already watched is what I'd suggest

Any of the long classics.

One Piece https://anilist.co/anime/21/One-Piece

Bleach https://anilist.co/anime/269/BLEACH/

Naruto https://anilist.co/anime/20/NARUTO

Dragon Ball https://anilist.co/anime/223/Dragon-Ball/

Cardcaptor Sakura https://anilist.co/anime/232/Cardcaptor-Sakura/

Mushishi

Show was so chill I drifted off to it a couple times.

Put The Endless Eight from The Melancholy of Haruhi Suzumiya on shuffle/loop and you'll have no idea how long you slept

For me, anything that falls into the comfy category. But probably more so stuff that has minimal verbal stuff.

I could probably fall asleep during most isekai; no pressure at all to pay attention since actually reading the subtitles will usually make the show worse.

edit: I just remembered this quote from a Mamoru Oshii interview:

Nishio: Angel’s Egg was only 70-minutes long, relatively short work for a feature length movie, so people who fall asleep when watching it really have low literacy, don’t they? Visually speaking, there are a lot of stimulus in it and the music is very dramatic, it’s totally watchable.

Oshii: I don’t mind people fell asleep at all. Since I wanted to emulate that Tarkovskian atmosphere in animation form. A pleasant and unbounded time. Films that make people fall asleep are good films.

So I guess his films are fair game lol

Sleepy princess in the demon lords castle

Quest for Odin is the only anime I have ever fallen asleep during. Take that as you will.