There are a large number of foam crafts out there for kids to do. I use a lot of them. A lot of them are perfect for toddlers and can be completed with little or no help from you. You can also find them everywhere and for very little cost.
Here's an adorable little visor Jamie made with no assistance from me. The Cars sticker pack came with stickers, glue and glitter. Jamie felt it necessary to glue the stickers on because he just loves playing with glue! He's so funny.