I don't believe 3yo need specifically STEM toys, but to add on the other good suggestions - Keva planks or just plain wooden blocks in all sorts of sizes. Mar

I don't believe 3yo need specifically STEM toys, but to add on the other good suggestions - Keva planks or just plain wooden blocks in all sorts of sizes. Marble run (if your kid won't eat the marbles) Spirograph (there is a crayola version thats easier for smaller kids)