My nieces made the Passover stamps in a neighbourhood art class out of pieces of wood and foam. Stamps can be made using scissors, an xacto knife or a carving tool.Depending on skill ability you can decide whether they can do simple or complex shapes. Older children could choose more complex designs, if they wanted. For more ideas see this carving tutorial.
For younger kids you can provide some holiday shape stencils that they can trace and cut out, or buy foam die cuts related to the holiday that they can glue onto wood blocks.
My nieces also made letter stamps as part of this activity, however, I didn’t photograph them.
These are useful for general pictures towards Passover, but they are also good for making place cards for your Passover seder.
If you make any, please share them with us!