There are lots of great Sonic blogs here on Tumblr! Here are a few of my favorites!
Sonic Multiverse (Fyeahsonicthehedgehog) — If you like my collection blog, you’ll enjoy this one. The mod makes a lot of merchandise posts, some of which even I haven’t seen before! The posts consists of a single image (sometimes a couple more) and no description, but they also come more frequently than mine, so it’s a good way to get variety fast. This blog also posts gaming screenshots, comic pages, fanart, and does some in-character replies to questions.
Fuck Yea Sonic — Much in line with the blog above, although it has a higher percentage of fanart, I believe.
Fysonicsatam — Specific for the SatAM fans out there! This blog mostly revolves around screenshots from the TV show, but it also features fanart from time to time. I think it actually has one of my animation cels posted, too.
Sonic Autocaptions — The premise of this blog is simple: Watch Sonic cartoons and cutscenes on YouTube, turn on the autocaptions, and enjoy the outcome. Sometimes the proposed captions can be really outrageous and unexpected!
Sonic Screencaps — Exactly what it says on the tin: A blog that specializes in screenies from the games and TV shows. A great resource for desktop wallpapers, if you ask me.
Nanite City — This blog’s specialty is excerpts from the Archie comics. Not only is it a great place to see some of the most epic moments and best art from the series, but the webmistress is one of my besties here on Tumblr! She’s got great taste, so if you like Archie, you’ll love this blog.
A Moment of Archie Sonic — While this blog also focuses on the Archie comics, its goal is the derpy, nonsensical, what-were-they-thinking moments rather than the most exciting and dynamic. It doesn’t see as many updates these days, but it’s definitely worth diving through the archive. The mod also posts periodically about Sonic-related news topics, and has several posts delving into the madness of Ken Penders.
Launch Base Zone — This is a laid-back and relaxing fandom blog. It focuses largely on fanart, but also posts some screenshots and youtube videos from time to time as well. This is a nice pick for a casual fan.
Fastest-Thing — The buck stops here when it comes to Sonic fanart. There are several updates a day, the content rarely repeats itself, and there’s a lot of variety. Some art blogs focus on specific characters or pairings, but this one covers the entire spectrum. There’s also a smattering of art from other fandoms as well, however, so it’s not purely for Sonic fans.
Well, those are all the blogs that came to mind for me first. Maybe we can do this again sometime and get more plugs for great blogs!