I'll just assume that you said free games. Ahaha.
I'm not really a fan of hidden object games but there are a number of a few that I have personally enjoyed.
Free iPad Hidden Object Games:
1. Found - (I know that it's the name, I just can't remember quite well, it might not even be the one I'm thinking of) Anyways it has good graphics, and a well made story line (for me atleast)... Well that's all I can say, sorry.
Paid iPad Hidden Object Games:
1. Vacation Quests - Now we're talking! Take on and look at the scenes of places while trying to find the objects you're looking for, make sure you pay attention though because you might get captivated by the amazing views. Story line is fine. And it is definitely worth the money that you paid for.
I added the paid one just incase you might want it too.