A good children's game does something harder than it looks: it gives a six-year-old real decisions while keeping the rules small enough to hold in their head. The best ones are cooperative, or close to it.
One caution worth repeating: the age printed on a box rates the rules, not the content. Check the artwork yourself, and set the Age filter to your youngest player rather than the average.
How this list is chosen
These five come from the same query that powers the finder, run with one filter pre-set. Expansions are excluded, so everything here is a game you can buy and play on its own, and only games with at least a hundred ratings are eligible.
Ranking is by community rating adjusted for how many people voted, not by raw average — otherwise a game rated 9.0 by a hundred devotees would outrank a classic rated 8.6 by forty thousand. The full method is here, and you can set your own filters to narrow this further by age, complexity or player count.