Maybe this is something I worry about more than I should, but I think a lot about the kinds of shows my kids watch. Because that stuff does influence them. For the parents out there, I had an idea to start a thread where we can list kids shows that are solid choices for us as leftist parents. I'm not expecting some cartoon characters to start discussing dialectical materialism. But I'm thinking shows that highlight values like empathy, community, etc. I would also include shows that simply avoid a lot of capitalist bullshit or cop worship (hard to avoid that one in kids shows, surprisingly). Also, we can use this thread to list shows we think kids should avoid.
Some of them that I came up with:
Mister Rogers Neighborhood - Fred Rodgers, while I don't think he was explicitly a leftist, really did seem to focus on really good things. Might be hard to get kids interested in a show that looks as old as this one, but it's honestly pretty great.
The Joy of Painting - Just a chill dude painting landscapes. Wouldn't think of this as a kids show but my kids loves it. I have friends with kids who say the same thing, too.
Eleanor Wonders Why - I like this one because the titular character observes the world around her and then wants to use science to explain what's going on. Just like our boy Karl Marx!
Daniel Tiger's Neighborhood - In general I think PBS does a good job in most their shows of not promoting capitalism or bourgeois values. Daniel lives in a neighborhood that doesn't have the obligatory "good cop" in it, which is good enough for me. Overall seems solid.
Bluey - this show is pretty great, I love it. However, keep in there's one episode that's devoted entirely to troop bootlicking (really gross for a kids show), so just skip that one and you're good.
Doc McStuffins - this show is ok but I'm recommending it because the lead character is POC, and even in 2021 I'm kinda surprised by how many shows still feel they need a white lead character with POC characters off to the side.
And a show I'd recommend against is Paw Patrol, I think for obvious reasons. I'll stop here and then add more in the comments as I think of them. Please share yours!
You'd need to go dig through the channel and find specific videos, but if you want something explicitly leftist, the YT channel NonCompete has a number of videos with puppets to explain leftist concepts. It's been a long time since I've watched any of them, so can't comment on how kid friendly the language might be, but this is the first thing that jumped into my head.
It is also most likely pretty far off from what you're looking for.
I mean I love the idea of explicitly leftist kids videos, just that I've got low expectations of finding anything like that.
Welp, then definitely see if NonCompete might be something the kid would like! THe puppet videos are pretty endearing, and there's definitely some clean jokes in there as well for adults (a horse being named "Gluey," a robot named "Krobotkin," stuff like that).
I love his puppet videos, and I feel like it fills a need for leftist content that targets younger viewers. We really should unironically be indoctrinating kids with communist ideas every opportunity we have.