I haven’t met a kid who doesn’t love play dough! There are tons of recipes online that you can use to make your own play dough and let your kids help. You can even make edible play dough! I love watching kids imaginations go wild with a ball of dough. They can come up with some of the most fantastic creations.
If your kids are a bit older, they might enjoy advancing to actual clay. This takes a bit more finesse to work with, but can be just as fun. The wonderful thing about working with clay is that your kids can make useful items that can be kept. They can paint these items and create wonderful works of art.