Sonic lore is hilariously messy. It gets absolute batshit when you start getting into the Archie comics. There’s more than enough to keep going forever, but at some point you need to address your own brain oozing out your ears and stop.

There’s some minor stuff I left out, like how Mecha Sonic (Game Gear) is often called Silver Sonic to differentiate it from Mecha Sonic (Mega Drive/Genesis) when talking about the games, but Mecha Sonic (Mega Drive/Genesis) is canonically named Silver Sonic in the Archie Comics. Both of those are different from Silver the Hedgehog, who is from the future that alternate dimension Nega Eggman (mentioned in the other comment) is from.

And seriously, the Archie comics timeline is insane. This is from the “Metal Sonic Series (Archie Comics)” page on the Sonic Wiki, and it’s notably not the only robot doppelgangers-of-characters “team”.

Like how do you even start with that? First Robotnik War? Metal Sonic v3.0 is separate from the other versions, but spoiler: he isn’t the same 3.0 from Sonic Rivals 2. Mecha Sonic is a separate entity from Silver Sonic?

Also, presented without comment: Psuedo-Sonic from the Archie comics.

People tend to think of the old Star Wars Extended Universe as the classic over-detailed lore, but the Sonic Archie comics are way way up there too. It was the longest running monthly comic book series to never be relauched, with roughly 512 total issues if you count the spinoffs.

Cybershell is an old Something Awful goon who’s made plenty of Sonic videos, but I think his Archie Sonic retrospective/postmortem is an entertaining overview, if heavy on using the word retarded. Was totally aping some of his attitude for that shitpost of a comment.