I love this craft I made with my daughter the other day! It is so cute and gets kids in the holiday mood for St. Patrick's Day!
For this craft you need washable tempera paint in all the colors of the rainbow, and black for the pot of gold. Then you need gold glitter glue, construction paper (I used gray so all the colors of paint would show up). I also used a sticker of a leprechaun that came in a pack from Dollar Tree, as well as a circle sponge paint brush.
First, paint the black pot on the paper, or have your child do it. Then instruct them to dip the circle sponge paint brush into each color, one by one (you'll have to rinse it in between) and then put them in arching rows like a rainbow coming out of the pot.
After that the black pot should be pretty much dry, and your child can use the gold glitter glue to top the pot off with! Then the sticker can be added as well if you have one.