Here is a project I did with my kiddo. I had her choose an image on Google image search that we could 3D print and include magets for her chalkboard. The robot is designed for dual extrusion but can be merged and printed a single color.
Load both models into slicer, select your colors if dual extrusion (skip this step if single color), merge models, and print. 0.2mm layer height is sufficient and support will be helpful for the magnet holes.