What are some things that you like to watch in the side or in the background when you do stuff ?

Nothing.
I can only focus on 1 thing at a time and there's already 20 of them at once at any time in my head.
But I can listen to music. Although it depends on what it is. But not to worry, I can just listen to a single song on loop for hours non-stop.

I like watching magicians do magic tricks while I drive, and trying to spot the technique.
I’m just kidding don’t do that
- Holy shit this would have been an amazing line for Micheal Scott to say
  
  Michael the Magic

Might not be up your alley, but there's a dude called "Just Background Noise" who does various Morrowind challenge runs. It's neat stuff, but his name is quite accurate. Makes for some great background listening.

I always have Lofi Girl playing quietly in the background when I'm working.
- Valeur sûre

Northernlion/The Library of Letourneau, he plays videogames and just kinda does a stream of consciousness thing that often has nothing to do with the game itself. It's entertaining and he has a nice voice.
- +1 for NL and librarian's cuts. Just got into him 2 months ago, super good for background stuff

- I believe that’s the same source as Pluto tv, if not, Pluto tv also has those channels
  
  we really need to set up a Discord server where people can live chat all the Pluto TV channels

My son loves the podcast Behind the Bastards. I like animal documentaries.
- It's a fantastic podcast! But I feel like it's kinda too good to have it in the background

Do you like silly stuff? I usually put on the YouTube channel Drawfee. A group of artists take ridiculous prompts and draw them on the fly, and the idea usually mutates mid-drawing based on their conversations.
Might not be great as you have to be able to look up from what you're doing to see the drawings. I'm more of a multitasker so it works for me.
- drawfee mentioned! I also watch Secret Sleepover Society, their game stream

Lately I've been going through my favorite artists and listening to their music in chronological order.
I hate the "pick something to listen to" phase of music listening, full albums let's me control what im listening to while not needing me to maintain it.

Trackmania gameplay. It's an arcade racing game, purely skill based, no story to follow. Players will play the same track multiple times until they get a good time, that way you don't miss anything important if you look away for a while. Probably not gonna work for you if you're not into the game though.
- trackmania has that in common with basically all speedrunning streams/content. super nice to have in the background since it can be repetitive and you can pay attention if they get a good run going :)
  and there are people who speedrun probably every game you've ever enjoyed, so there is plenty of options!
- Yes! TrackMania footage is so satisfying. Wirtual's documentaries on the game are also great

MST3K, especially some of the episodes I'm most familiar with.
- That's weird because 'In the background while you do stuff' is Golden Corral's new slogan

Josh Strife Hays. Absolutely whelming 2nd monitor content.
- +1 for Josh, particularly the "was it good?" Series where he replays ancient titles start-to-finish while giving his thoughts about the game design.

LabPadre's 24/7 stream of SpaceX in Boca Chica. Sometimes watching concrete dry or debris removal is just what I need to take a step back.

i like listening to Lily Simpson videos when i'm doing chores and such. Her videos are often fairly long (meaning i don't need to stop what i am doing to pick another video), easy to take in without having to actually watch with my eyeballs the whole time, and of consistently high quality.
- Here is an alternative Piped link(s):
  Lily Simpson videos
  Piped is a privacy-respecting open-source alternative frontend to YouTube.
  I'm open-source; check me out at GitHub.

Time Team on YouTube, but it’s an archeology show so you really have to like that topic.
- Was about to say the same thing - just annoying it's not all available online in the UK
  
  There are a lot of episodes on YouTube, on there official channel and on other channels. Plenty to keep me occupied for a while.

Futurama. there's an entire subreddit for Futurama sleepers and I think it's the largest of its category

I often have ASMR videos playing in the background while I play chill games or at work. It relaxes my mind and helps me focus

Audio books are nice. I like short story collections where each story is maybe 20 to 40 minutes long.
- Any recomendations?
  
  I'm currently going to through the BBC classics ultimate story collection. I also liked the BBC radio 4 rendition of Dorian grey. The radio ones tend to have multiple voices and some special effects. I also loved the blade trilogy by Joe Abercrombie.
  If you like sci-fi, I can recommend the children of time and deepness in the sky. Vernor vinge also has a novella in audio format called fast times at Ridgemont high.

I currently have a Baldur's Gate 3 stream running in the background and she's just doing inventory management. My brain can't handle anything more complicated.

Anything from the Simon Whistlerverse, today I found out, brain blaze, casual criminalist, they're all good to have playing in the background, especially when Simon starts ranting.