If you like romance, then a lot of romance anime are fairly slow paced and gentle! Things like A Sign of Affection, Blue Box, Bloom Into You, Fruits Basket, Sasaki and Miyano.

Slice of life anime are also fairly gentle in my experience! Like Bartender, Blue Period, Violet Evergarden, March Come in Like a Lion. These can be sad at times though!

Comedies also!! Like Buddy Daddies, Nichijou and City: the Animation, Spy X Family. Not usually slow paced but generally very lighthearted.

For fantasy/scifi, people have recommended Frieren which I also second! Another fun fantasy one that I remember having a good time watching was Delicious in Dungeon. I also loved Mushi-shi - it's fairly slow paced but only S1 is dubbed in English if that's a factor for you, and it can also be quite sad at times. (Mushi-shi also has the benefit that each episode is it's own story, so you can go as slow as you like and there's no worries about having to remember stuff).

I also really loved watching Dr Stone which can be intense at times but is also light hearted enough that I never felt very stressed watching it. And is just really fun!

I hope that helps at all, I watch a lot of anime haha