Here’s some ideas:
Ready-paid gas cards for him to fill his tank at a filling station near the church. Priests put a lot of mileage on their cars.
Ditto for a credit in his name at a local repair/filling station. Or go as a group project and take his car in for new tires and a rotation/balance if it needs it.
Gift cards for local grocery store. Priests have to eat too.
Amazon.com, TAN Books, Catholic Book Club… whatever… gift card to that so he can build his library and get books for his own continuing moral/spiritual education. One parish I was at, they gave us a list of books a departing priest wanted, and we all picked out one we’d pay for and signed our names to the book plate and gave a check and the lady handling it got the books.
All Father had to do was go through a long list and make up his wish list.
A certificate of hours donated to a project at the church… gardening, repairs, something to help.
Movie theater/Blockbuster cards. Priests like to go to the movies too.
A gift certificate to a good shoe store or shoe repair shop. I notice eventually priests all get a cracked sole on their right shoe from all that genuflecting.
And cash. If you want to be innovative about it, use it as gift wrap for a bucket of golf balls. (Are there priests who DON’T play golf?)