Shouldn't put buttons on them (choking hazard) but these would be easy to do from felt or blanket material. Like the jingle bell inside. cute little baby rattle. free pattern and you use jingle bells for the rattle part.
DIY Dual Duty Perler Beads Coasters or Drink Covers Tutorial from Loppi.These coasters/drink covers can be made out of Perler or Hama Beads - so they are very cheap and easy to make. For lots more Perler Bead DIYs go here. The video is not in.