I’ve sent money to openbsd.
They might not be popular to use, but the absolute freedom of the software along with how simple it is written makes it an incredible “good” for studying OS design.
I have also donated to the FSFE (European FSF) and the Linux foundation, but we don’t get tax incentives for donating to charity in most european countries. So it’s quite costly.
In the past I've donated old hardware to OpenBSD [1] and would love to donate to them directly, but they aren't registered as a 501c3 in the US and can't claim the deduction on taxes (yes, I know, I am not 100% altruistic).
Instead I donate to FreeBSD and support OpenBSD in an ancillary way through OpenBSD Amsterdam [2]. Which yes, is also not tax exempt, but does comes with nice OpenBSD VM.
Sending money annually to OpenBSD myself, as the operating system brings me a lot of joy for how integrated and predictable it is. Sending money to Sourcehut, although that is not a donation, and FreeBSD in the past.
I also donated to the FSFE, they're doing such important work in the EU at this time.
thanks for your donations... I use openbsd on a daily basis. Like you I love its simplicity. I love how few processes are running at anytime and how easy to tell what they do.