My 3 year old loves YouTube kids, and I'll admit he gets a good amount of it. We make sure we're watching it with him, and we control the remote. Some channels/topics we all like:
- Aty and Ui, two pet otters in Japan. Their owner has made tons of videos showing what they eat, how they play, and the different rivers they visit. All dialogue is in Japanese and English subtitles. My kid now loves otters, I explain different things about animals or Japan to give context, and I get to practice reading Japanese.
- MIKAN, a channel with videos of "marbles" animated using a basic physics engine. There's no dialogue. There are races, factories, battles, and even a tower defense match. It helped him learn colors. Nowadays, he gets up and practically dances while cheering for his favorite colors. Indoor exercise isn't so bad. Some of the videos that aren't on YT Kids can be a little scary for toddlers (like alien abductions, not the dreaded shock schlock that pops up on YT).
- 5MadMovieMakers, a channel with marble runs and Hot Wheels tracks. No dialogue, just short clips of creative tracks with background music. My kid now loves coming up with his own marble and Hot Wheels tracks now (though he's still not good at planning out the whole thing to actually work).
I understand the concerns about using YT Kids as a babysitter. When he gets a tablet at my parents' and decides what to watch, it's things like cars driving over paint-filed balloons or the typical group of bros overreacting to a different stupid thing each week.