Yubikey + gpg-agent (w/ SSH support) on Fedora 27
Note: This assumes that you have already generated your GPG keys (i.e., offline master key + subkeys) and have them in your Yubikey.
Recently, I switched from Arch Linux to Fedora 27 on the hosts that I use daily (my workstation, my "primary" laptop, and a "secondary" laptop). As best as I can recall, here are all of the steps I had to do in order to get things working in addition to some notes ("quoted") that I made at the time.
FWIW, this is greatly "summarized" but I think I've included most of the important bits. It's very possible that I've left out some pieces, though, so feel free to let me know if I've missed something.