If you are looking for a FOSS alternative to tonies, yoto and such I would also recommend the DIY TonUINO project.

The boards are built into boxes, toys (from fire engines to plush) and whatever sparks imagination. https://discourse.voss.earth/t/tonuino-gehaeuse-galerie/786/...

Most of the community speaks German, but there is also an English section https://discourse.voss.earth/c/international/11

The source code is in English and the schematics language independent. https://github.com/tonuino/TonUINO-TNG