“Man toys” usually refers to things that an adult man might buy for entertainment and that are typically associated with men rather than women. Example: an off-road motorcycle. A related phrase is “man cave” — meaning a room in the house where the man of the house, and maybe his friends, hang out to do “manly” things: e.g, watch American football, drink beer, play billiards, etc.

Can you please give me more context as to how you heard this expression? Without knowing, I would guess that "man toys" are gadgets or literal toys (like action figures) that men collect or enjoy as a hobby.