How do I sign out of my Apple Account on a remote device that is not connected to my account?

I recently lost my iPhone and used someone else's iPhone to successfully find it. I signed into iCloud.com/find using Safari on their iPhone with my Apple ID. When I found my phone, I forgot to sign out of their device. When I login to my Apple account, their device does not show in my list of devices, so I cannot sign out remotely. How can I get a list of everywhere that my Apple account is signed in and choose to sign out of some of those places? I don't want my Apple account to remain signed in on someone else's device. Will it automatically sign out at some point?

[Re-Titled by Moderator]