The EU's safety rules for children's toys are impressive -- I read them out of curiosity when I was 3D printing a toy.

e.g. dropping a 1kg steel block onto the toy, and checking it doesn't break in an unsafe way (section 8.7 in the link).

https://law.resource.org/pub/eu/toys/en.71.1.2014.html#s8.7

Section A.51 is about magnetic construction toys.