OpenKeychain and Password-store (paired with a yubikey) is the entire reason I use Android over iOS. I really wish there was hardware GPG key solution for the iphone.
I've been using pass with a yubikey for the past year and a half and have been very happy with it. The ability to call out to the pass binary in personal scripts is a really handy feature that I didn't realize would be so useful until I started using it.