The Tiny d6 system has several ruleset for different genres and it's pretty easy to pick up.
Thanks everyone, I'm checking it all out now!
I know this is an old post, but I will give a +1 to Hero Kids for a few reasons:
There's like 4 stats and all you need is a bunch of D6.
The character sheets fit on an index card and are easy enough for a 6 year old to grasp everything on it.
If you want to run their setting, tons of info is provided with quest seeds and pre-made adventures, and it is super easy to adapt to a different setting, or even totally different genre, because of how simple the stats are.
It has a great monster compendium, with tons of fantasy monsters, with notes on balancing encounters.
If you want to get creative and make totally custom monsters, the information included on balancing gives you all the tools to do that.
The PDF bundle on DriveThruRPG is like $20 for the PDFs of most of the adventures, the core book, the monster compendium, and the gazetteer, all of which are great.
I'm running an ongoing campaign with a 6 year old, a 7.5 year old and my 16 year old sister. We had a 3 hour session last time, and the ADHD 6 year old was there for the whole thing (with a couple 5 minute breaks).
If you have any questions about it let me know. I'm not a super experienced GM. I've only run Hero Kids and Genesys, with being a GM in Hero Kids being my intro to TTRPGs.
Just understand that playing a game with kids that young means throwing out the rules as soon as you start. So you need something with absolutely minimal rules (or you're wasting you time) and a story that's easy for them to latch on to.
I love using Honey Heist with kids. It's basically Lasers & Feelings, but you're a bear disguised as a human trying to steal honey from humans. Kids can really take that premise and run with. If you run multiple sessions do it picaresquely, where each session is a self-contained episode.
do it picaresquely
Thank you for the new word! I'm sharing it in the community I put together to share new, fun words I find!
Also, thank you for the game suggestion! My children are older and I am able to play more complicated games with them (typically Pathfinder) but my niece is getting older and in a couple years I'll probably try Honey Heist with her!