My mother in law keeps buying me UGLY stuff for my baby!?

Gently and kindly explain to her that you will be doing something different as a theme for the baby. Then tell her instead of buying specific things, you'd appreciate it more if, when she wanted to give you a baby gift, to just give you a gift card from a baby store. Just tell her you could use that more so you could get things that will fit into the decor you're planning.