FairEmail is a privacy oriented email app on fdroid which uses donation to activate pro features. €0.10 to activate one time and €7.50 for unlimited future devices. I think it's a pretty fair deal. https://email.faircode.eu/donate/
It's a fair deal, but the point is it's not a donation. You can purchase pro features, and that's great. But it's not a donation if you get a product in return, that's just a purchase.
Not if it has all the essential features, it has no 3rd party ads, tracking and is a privacy focused mail client.
I only bought i because i could test it for months and saw everything works and it being updated and well maintained, it's kinda pricey for a mail client.
There are for sure nagging experiences in other programs, Fairmail is not one of them.
But honestly i don't really see what's wrong. There's a base donation for the price of the software but it just give the option to support the dev if you want...
I mean most things that rely on donation like that are just cheap indie software (I think voicemeeter was $5)
I'd take that over the awful and greedy subscriptions that cost an arm like adobe or Microsoft.
OCCT doesn't require you to purchase it for personal use (although you will get a 10sec timer before you can start a benchmark/stability test), which is why i think it doesn't count as "donationware"