Soft toys are a sensible starting point for a first rotation, because they store flat, have no loose parts to lose track of, and can be swapped without needing to think about batteries, instructions, or matching pieces. The soft toys collection at Nestoro includes Best Years' organic cotton sea creatures and bunny rabbits alongside Nestoro's own personalised teddies, and either range works well as a rotating set: a handful out at a time, the rest boxed away until the next swap.
Rotating soft toys specifically, rather than starting with an activity toy that has multiple parts, keeps the whole exercise low effort. There is nothing to lose, nothing to reassemble, and nothing to remember beyond which box came out last.