How do I add loyalty cards to the iOS wallet? Is there any way to add loyalty cards to the iOS wallet? I'm talking about those mini keyring cards. Or any arbitrary barcoded card, like my library card. 

I'm interested in OS provided methods, first. When I scan my cards it says no codes or passes found or something. Not very helpful. 

The support forums seem to indicate that I need to install specific apps for every card. Forget it. 

And these loyalty card and wallet enhancing apps all seem rather sketchy.
I use PassSource, and it's very handy!

You don't need to download any apps or even create an account. You just use your iOS device to go to their website, input information about your loyalty card/coupon/ticket/etc., and tap "Add to Apple Wallet".