Will you help me put together a list of unique gifts for kids ages 2 to 13 the kind that can't be found at Walmart!?

I’m going to keep it simple, and give the same gift to 2 or 3 kids at a time, out of the 15 grandkids we need to buy for, so I need a list of about 5 to 8 unique gifts.

In my other question I noted I have decided on a rock polisher for 2, possibly 3 of them (all in different houses.)

I lean toward scientific/educational things like a rock polisher as mentioned or a metal detector (which are two things on my list.) I really don’t want to go to Walmart at ALL if I can help it. Plus, they don’t normally have anything particularly unique.