Gravity Maze Marble Logic Game
If you buy one thing on this list, make it this. A challenge card shows where the marble starts and where it has to land, and the eight-year-old has to build a working tower of clear chutes to connect them — then drop the marble and watch whether their plan actually holds. It's a single-player logic game with sixty graded challenges, so it scales from "oh, that's easy" to genuinely head-scratching, and there's a real payoff at the end of each one: the marble either makes it or it doesn't. That instant, honest feedback is exactly what keeps a kid this age coming back instead of wandering off.
Builds: planning · spatial reasoning · persistence
~$20· See it on Amazon