I think LetsEncrypt (ISRG) is one of the best examples when it comes to donations. They have a super small budget and a very small staff, but they single handedly made pretty much every web site today encrypted. One billion certificates issued so far, and the rate if it is only going up.

If you have a budget to make some donations, please out LE on the top of the list. They are doing a wonderful job and you are will make a massive change.