I want to take this opportunity to thank you for bringing awareness about the relentless work of uncountable people in this community (be named or anonymous), devoting themselves to share expertise for free, regardless of their time, social position or economic status.
I personally believe that this community built a system in which generosity is spontaneously returned. Speaking for myself, I arrived here almost a decade ago, coming for help, as pretty much everybody else. Then, unsurprisingly, I stayed due to a strong feeling of gratitude and closure.
My path is probably not too different than anybody else who is a contributor to this community, as well as in the TeX world outside. I made friends (personal, close friends, by the way) with so many people here. I managed to come up with so many TeX-related projects because, back then, at a certain point in the very beginning of my path, I was given encouragement and confidence from people in here when I surely need them most than ever.
Your initiative is very noble.
An anonymous donation is a bit complicated due to how electronic transfers and bank deposits work. So we need to think of something in the meantime. Some contributors offer sponsorships in their GitHub profiles. A donation to TUG is always welcome.
That said, when it is not possible to directly express your gratitude to TeX contributors, and I believe I speak for a significant amount of them...
Spread kindness around you.
Do it so gently, do it for your community. Read to residents at a nursing home, donate blood, volunteer to help at a charity auction, tutor children in schools, donate stuffed animals to children in hospitals, knit blankets to be donated to hospitals or homeless shelters, donate books to a school library, teach computer skills to the elderly
(that includes Microsoft Office), mow an elderly neighbor's lawn, take care of cats and dogs at an animal shelter, plant a tree, sponsor an animal at your local zoo, donate your old clothes, volunteer at a soup kitchen, and so on. Start volunteering! I am sure you will do great, and every TeX contributor in this community will be greatly honoured to realize their selfless act of knowledge sharing sparkled an actual good being done in this world so full of racism, prejudice, hatred and bigotry.
I do not know you. But I can tell you are a good person. I am sure you will make a difference!