This is a list of stuff we've used. But I bought it mainly because it was cheap and I like to have a lot of different things on hand. We also use workbooks, computer programs, and plain old pencil and paper.
So seriously, check the sales and buy what is cheap and looks interesting. Don't take this list as being in any way absolute. I don't pay full price ever, and then I don't mind taking minor risks on school supplies. You can get stuff for 50-80% off. Maybe not this particular stuff now, but I did buy all of it on deep discount.
In addition to pattern blocks (which were out on our floor pretty much every day for either art--Transformers!--or math every day for a year!):
* dice, including ones with +/-/x/divide and/or fractions and/or whatever else mathy that you can find: great for arithmetic games, statistics and probability, homemade board games, etc.
* balance scales that can be used for algebra. I wouldn't pay full-price for these, but they are good for illustrating negative numbers and algabraic concepts.
* Plain old wooden cubes. Useful for arithmetic, fractions, pattern making, creative problem solving, etc. Plus they can build stuff with them.
* Tangrams. Good for problem solving and spatial thinking skills. And the pictures are pretty.
* Self-correcting math games. These can be electronic, like hand-held video games. But a favorite was these plastic key-type things that had math problems on them. The child matched question on one side to the answer on the other with string, and the wrapping made a pattern on the back. If the string pattern matched the answer on the back, the child got it right. This kept both kids busy in the car for many a long trip. I have no idea what it's called, but I think we got it through Usborne Books. I've seen other things like it though. The self-correcting is the key, regardless of what method it uses.
P.S. You know that
www.homeschoolbuyersco-op.org offers Descartes' Cove for a discount, right? It's $105, and the deal lasts until 3/31. See
https://www.homeschoolbuyersco-op.org/index.php?option=com_hsbc_epp_order&Itemid=1166