How about some packs of Sculpey, a plasticine clay you can bake?
I like art suggestions...
Metallic colored pencils (get some colored card squares for this, so they show up nice and bright)
Book of construction paper or multicolored pack of cardstock.
Scissors which cut in shapes/patterns
Glitter glue (have then do this on placemats or use a dropcloth)
Stickers
Little 'scrapbooks' they can put pictures and mementos in and decorate (you can even use notebooks and cardstock with 3hole punch)
The Orb Factory makes Sticky Mosaics ... my six year old son LOVES these. They have a load of patterns.
The Scratch-Magic Doodle Pads are also a huge hit with our boy. Just be sure to use a few paper towels/ a tray under them to catch the black coating as they scratch it off to reveal sparkles, rainbow, etc. He did this for about 40 minutes during a long Thanksgiving dinner this year. That book saved us!
We also love the wooden Pattern blocks in our house. We use them with some of the non-skid drawer-liners (that rubbery fabric--I cut it into 10"x12" pieces) so the tiles don't slide and so my son can keep his creations.
Here is a buyer's guide I really like from Growing Child... you can scoot around the pages and see if something pops out at you.
http://astore.amazon.com/growchil-20?_encoding=UTF8&n...