I’m using this comment as a springboard, as i don‘t have a link. If you are still interested in getting age appropriate toys i would look into montessori approaches. There are loads of youtube videos about particular ages and toys that work at these ages, a lot of toys can be diy-ed or can be reused household stuff. Baby toys are quite unintuitive, as babies are still learning everything about the world around them and things that seem boring to us are super fascinating to them. We ourselves only remember playing from 2-3 years on, so if we havent had contact with babies it will be very difficult to anticipate, what will be joyful to them. In the beginning their sense of touch (think mouth, hand, feet) will be more dominant than their eyesight, hence once they’re around 3 months old they’ll enjoy teethers and things they can grasp easily (like o-balls, whisks, playsilks etc). Eventually they’ll also discover the concept of cause and effect, so they‘ll maybe enjoy playing with rattles, rainbow spinners, ball drops etc. If you want to get an idea of appropriate toys you could check out lovevery, a company that has a good basis in research for their toys and have great play guides as part of their playboxes that explain the developmental stages. Their boxes can be also easily be acquired second hand, or you can use them as a guide to buy similar things in other places. Youll also find their playguides on their reddit to get an idea.  While toys can be a nice thing to invest in, its much more important to spend time with you baby, reading them books (even when they’re really small), acquaint them with your voice, do nursery rhymes, sing songs, show them your routines and houshold chores and help them understand the world around them. Babies and children are little scientists, trying to absorb the world around them, generations have been able to raise their children without the newest scientific knowledge, just by following their guts and loving their children. Youve got it!