Look up the CGDCT genre/rabbit hole. ("CGDCT" stands for "Cute Girls Doing Cute Things"). I am not a fan of the genre personally. But if you're a fan of the music element of it, and how music plays a role in the slice of life... Hibike Euphonium is a good pick. And if you want to go oldschool, Nodame Cantabile is a good comfy "music" anime (NOT "song" or "idol", it's about classical music, so if you're looking for Skrillex, you won't be Bach).

If you don't mind the random comfy slice-of-life being a romantic comedy, "Kaguya-sama Love Is War" is good watching, though it isn't the CGDCT genre.

For a less comfy, more drama, but still good slice of life anime that I enjoyed and doesn't get any recognition because of its age, "Myself;Yourself".

Lucky Star, Haruhi, Non Non Biyori, Sayonara Zetsubou Sensei, Joshiraku, Daily lives of highschool boys, Nichijou, Azumanga Daioh, Yuru Yuri

Yuru Camp is possibly the best SoL ever made. Season 2 is airing now so you can join in the weekly fun if you want after watching season 1. It's about cute girls going camping and eating delicious food. Also Ms. Kobayahsi's Dragonmaid is pretty awesome chill SoL. For shows more focused on actual comedy and a little less SoL try "Dagashi Kashi" or "Saiki K"

Just as an aside out of these 4 show dagashi kashi has the hottest chicks. It's this girl https://images.app.goo.gl/eJwerXrDNPPfZD4JA shes one of the best anime girls I now.

Oh and also if you want an almost exact copy of K-on! theres a new show coming out called D4DJ that's basically K-on but with DJ girls instead. https://myanimelist.net/anime/39681/D4DJ__First_Mix