Old episodes of MST3K. I don't know what it is, but it's really relaxing to watch. Puts me right to sleep if I watch it at night :)
I'm not saying this as criticism though, I love the show. It's just that combination of old movies with bad sound and the fact that I don't get a lot of the outdated jokes puts me in a very relaxed mood.
"Nailed it!" is my goto chill show, all the contestants are failing miserably at making fancy cakes but they're also not taking it too seriously and Nicole Byers keeps up a positive and encouraging attitude even when she's making cracks about the cakes.
Not sure if anime fits your bill here but Mushi-shi is incredibly relaxing and even though i don't really watch anime anymore it still jumps out to me when i think of chill/mellow/relaxing. Traveler investigating forest spirits and whatnot, soft Japanese music score, taps hard into those nature vibes, more of a rainy day relaxing though not really happy-chill.
There was another one I forgot the name of on Adult Swim that was just like videos of rivers/streams, fireplaces, and other relaxing elements put to a lo-fi girl style soundtrack. Look Around You? Or something like that. When they started that one, I used to fall asleep to it nightly.
Edit: Not Look Around You; that was the BBC science show parody. Also good, but not the relaxing thing I am thinking of.
I came here to say Joe Pera Talks With You. The entire series is a hidden gem, fyi, if you've only seen the "talks you to sleep" episode. I've watched all three seasons at least three times.
Taskmaster, every season has 5 comedians complete a set of tasks and be judged on them by The Taskmaster. All so they can win a golden effigy of the Taskmasters head.
Very good show Season 18 just wrapped up. There are some other countries that did good spinoffs like New Zealand and Australia, and others that didn't America.
Forged In Fire. Each episode 4 blacksmiths compete to create a blade with limited time which each round someone being voted off by judges. When the last 2 are remaining they are sent home for a week to make a historical weapon to be tested by the judges.
Very wholesome, judges are kind and will explain how it went wrong and how they can improve their techniques. One of the early winners even goes on to become a judge.
Jinny’s Kitchen, which is on Amazon right now. It has different titles depending on the cast member's name they want to use for the season. It’s basically a bunch of Korean actors/celebrities that are tasked to run a pop-up restaurant for a week. I like that there are no egos and they actually hunker down and do the work. No American tv show style drama. It’s a good show if you just want to watch something and not want to think or understand plotlines or dialogues.
Maybe a little out of left field, but the animated show Star Trek: Lower Decks. I'm not much of a Trekkie at all, but Lower Decks is funny, endearing, and even though each season has an overarching plot, much of the episode plots are relatively self contained.
My dad watches Full Custom Garage, and while I'm not interested in cars or anything like that, the guy's personality seems so positive, and the show is so drama-free, that I could just watch it and relax without hearing any assholes arguing at each other like some other shows.
Shrinking is pretty chill. Kind of reminds me a little bit of Ted Lasso in that people aren’t total pieces of shit and try to learn from their fuck ups. Also, Harrison Ford.