What's your babies favorite toy?

Abbigail • Married and expecting a little boy on May 16th, 2016!! 💙😍 we love him so much already!
Trying to find new toys for my son. He is 3 months old and just started playing with them. He seems pretty picky though. What are your favorites? Has anyone used a water mat for tummy time? How did thay work? Thank you!!