First off, like Hornblower
said, there is only one dev programming SE with a few other community members who do other small things like nebula/galaxies/systems/etc. Vladimir is the one who receives all funding so he can continue programming and advancing the engine.
Secondly, I suggested Patreon originally but after reviewing their terms and how donations are made through Patreon it is not a good platform for SE due to the slow nature of updates and the inability to promise people goods and services for being patrons. The best platform currently would be a flat no guarantees donation, like there is now, and eventually selling the program on Steam giving people early beta access and Steam features, while the program will remain free on the site. The Steam launch should be some time this year.