Amelia has a thing for matching. Shoes, socks, matching songs on Pandora to toys or pictures in books (like, if the Itsy Bitsy Spider comes on Pandora, she has to find a picture of a spider in a book - same thing with Winnie the Pooh, etc.).
I made a simple matching game for her by just cutting some flashcards in half. I had the flashcards from when I taught preschool and I know I got them at the dollar store.
The BEFORE cards
I spread all the pieces out and she finds the matches.
As you can see, sometimes she picks up the pieces with the wrong hands. She's learning to switch them so that it makes a perfect picture!