Sonic fans, or as so eliquently put from some people on the Internet, Sonicfags, are a group of people that enjoy any type of Sonic the Hedgehog related media. Often times, this is irrespective of the games, and more towards the TV shows or comics of the character. If you know anything of Sonic's out-of-game lore, you'll know that it goes quite deep. This wiki article links to other articles on specific Sonic fans, and even some people who have worked on properties that have the character in it.
Tamers12345 is a YouTuber that has continued the Sonic Underground cartoon series for over a decade now. His channel can be found here. A wiki page on Tamers will be made in the future, no promises but I will attempt to cover the entire saga.
to be written. (more of a general weirdo, might move to a section on weird fetishes).
Alix Henriol is the founder and now vehement denier of being the founder of the site "Sonic Passion". I'm nowhere near an expert on this person, so I'll just list some helpful links.
A good collection of screenshots from Sonic Passion here ED page.