If you can’t find the supplies you need, look at thrift stores. Goodwill and other similar stores have a lot of stuff for clever crafters. You have to check regularly, because the stock moves quickly.
Look on the internet for new ideas about arts and crafts. Sites make how-tos and ideas available to you. Regardless of the age of the participant, there is likely a project for everyone.
If you love sculpting, but have run out of ideas or are stumped about what to create, get a blindfold. People who have some skills with sculpting can create amazing pieces when they simply use their minds and hands! Set yourself up as you normally would, and just put a blindfold on, or close your eyes and let your imagination go.