I can't say about all of them, but the RiF developer clarified it for the verge, taken from this link :
If RIF is still working for you when you’re logged out, here’s why.
“When users are logged out, the app is still working because it does not use the OAuth client credentials while logged out,” developer Andrew Shu tells The Verge in an email. However, he expects that the app will stop working in this way soon.
Sync is no longer working at all, only error messages, maybe they didn't revoke their keys, that might be a nasty surprise for those devs when they get the bill.
I’m guessing some app developers didn’t delete their API key like Apollo did but I could be wrong. Not sure why Reddit hasn’t pushed the 429 error out to all apps, only some, though.
Narwhal for iOS is working as well as ever. However, the developer is apparently eating whatever the API cost is right now (if there even is any) and will push an app update soon that will require monthly payments to keep the app working.
The Relay dev thinks they can make a subscription model work. Last I checked they still hadn't determined pricing, but they were hopeful that it would be about a 60/40 split for them/the API. I'm skeptical it will work out that way, I have a feeling most of it will just go to reddit.
But the app will continue to work for the next few weeks before the subscription kicks in while the dev works out the details.
Infinity on Android still works for me, though I don't know for how long as I got a message about a week ago when opening the app saying it would switch to a paid subscription July 1st so I have no idea what is going on there.
I think Infinity secured some kind of exception to keep it running until the new subscription version is ready (likely because the app has always been free and not subscription-based). There was some discussion on the Reddit Infinity community but I haven't been on there in a while.
There is some suspicion that other apps like Narwhal are paying out of pocket to keep things going at the moment...