Yes my little ones have Kindle Fires. My older kids have iPads.   As for apps my little ones are very active kids so they do not spend a lot of time on a tablet and we use them most for travel in the car. I know there is a shark game that they like a lot but I cannot think of the name right now.

I limit this a great bit, but their favorites are the free Lego apps.

They don't have their own devices (aside from the 9yo's Kindle, which is a reader only) but I let them use my iPad. I didn't know about the Lego apps. I'll have to look at those!

When my kids were learning to read they LOVED Headsprout. Overall we didn't use technology too much, but there seem to be many more interactive programs for kids nowadays.