I have a 1 year old Son (who I don't get to see much 👿 ). But when I do get time with him, he seems happy to just press the buttons on my HRM to make it beep, or to be held upside down and walk on his hands across the floor. Just bought him a super small football, which he seems to like rolling around. Apart from that he likes to be bounced up and down on my knees. Simple minded chap like his Dad!
Seriously dude, just play the fool and make silly noises. Works every time.
Sure there will be some parenting "experts" along shortly to recommend the ultimate toy, which develops both intellect and cognitive skill. 🙄