Sanako might be a bit more popular than YouTube Kids. We know about 1 link to it since March 2021 and only 1 link to YouTube Kids. We are tracking product recommendations and mentions on various public social media platforms and blogs. They can help you identify which product is more popular and what people think of it.
Also there is featured YouTube Kids content like PragerU Kids and the upcoming DailyWire Kids. I'm sure that just like PragerU Kids, when DailyWire Kids launches it will be featured content on the YouTube Kids app. Gotta start the right wing indoctrination at the earliest age possible via kid friendly platforms like the YouTube Kids app. Source: about 2 years ago
Haven't tried them personally, but had run across https://sanako.com/ and https://withprimer.com/. Looks like primer is more for home-schooling though. Source: almost 3 years ago
Mashs and the Bear - Mashs and the Bear developed and published by 01Digital for Android and iOS devices.
Primer Rooms - Live, interactive experiences with kids around the world
BabyFirst - BabyFirst: Education Songs, Games, and TV for Kids is a safe and fun way for kids to sprout, start learning, and explore.
DIY.org - Any kid anywhere can learn any skill.
Kids First - Kids Videos and Nursery Rhymes – Kids First is a free kid education app developed and published by USP Studios.
Prisma LIVE - A live learning platform purpose-built for kids