You may or may not remember that I previous had made a highchair pad/cushion for my IKEA Antilop high chair (see here). Now I've made a boy version, since I can't have my little guy eating in a girly chair.
I used the same pattern as the first time, but forgot to make one change. I wish I had sewn some ribbon straps on where the back meets the seat. Sometimes when I put him in the chair, the cushion slides forward under him, and it would be nice to have some ties to tie the rear in place (there are 2 slits they could slide through—where the buckle straps feed through).
The fabric I used was left over from my crib skirt, and I've gotten a lot of mileage out of that material. It's from the Joel Dewberry collection called Modern Meadow. For the back/lining I just used an old navy blue t-shirt and recycled it into this. The whole thing cost me $0.