A playdoh press I designed for my daughter. It's a lot like the ones one can buy at a store (but where's the fun in that?). It comes with a dozen tips that hold securely and should be easy for small hands to remove. Some of the smaller shapes require more force to extrude.
All testing for fit was done using Hatchbox/Prusa PLA, 0.4 mm nozzle and 0.2 mm layer height. Print them as close to fully filled as possible for best strength, especially the plunger. No supports are required but it may help reduce clay tearing if the tips are deburred to remove the flattened first layer.
Standard Prusa PLA Sli3er settings