Apple also sells external keyboards with real F-keys. Their newer external keyboards are meh, but the previous model, the A1243 Wired Keyboard with Numeric Keypad [0] is amazing. It goes up to F19, and I just generally prefer their layout. I've been using an A1243 as my programming keyboard for nearly a decade. When they stopped selling them I even bought a used spare as backup for when my current keyboard dies.
My only complaints with the A1243 are that the top row is half-sized, and that it has a useless eject button between F12 and F13 which can't be remapped.
My only complaints with the A1243 are that the top row is half-sized, and that it has a useless eject button between F12 and F13 which can't be remapped.
[0] https://en.wikipedia.org/wiki/Apple_Keyboard#/media/File:App...