I've got a real gold-mine for you today!
-Shock and Awe by "UnderwordCircle"
Taking place in Archie Light Mobius 3000 years into the future, the Silver from the "Other" Future Timeline (the one that was "the result" of stopping Mecha-Sally) is sent back by his Echidna Mentor Edmund for that same mission (except there's a lot of traitors this time). He undershoots a couple of decades, and it turns out Light Mobius is doomed anyway (even after Sonic seemingly killed his first kids, and 20 years of his life, to save the universe). So now he has to go back to the Second Robotnik War (along with a stowaway Naugus-possesed Evil Shadow) to save his future once and for all.
The First Comic is Finished, the Second is a WIP, and the other 18-19 Chapters are temporarily in Fanfic format (with covers already prepared). It has details and world-building unlike any other Sonic Fan-Comic I've ever read. It's a fantastic story, just read it:
https://www.deviantart.com/underworldcircle/gallery/63284525/shock-and-awe-issue-1
-Sonic and Korra by "zavraan"
A simple crossover story with great art, awesome action, and surprisingly good character dynamics. Now I love Avatar and Legend of Korra, but Korra (in my opinion) started pulling a slow subtle Game of Thrones on us in the last 2 Seasons.
Her "controversial" ending with Asami felt more or less like forced Queer-bait to rake in the views (in my opinion). This is blacked out because people are probably going to think I'm a homophobe for this (welcome to 2020). The premise is simply Korra getting pulled from her world thanks to Eggman and the Emeralds, and Sonic comes across her looking for them. They lose their powers a bit later, so they have to learn to work together to get their powers back, and her back home. The good news here is that it's already finished (albeit, the author forgot to sort it so I have to rely on another user who did it already):
https://www.deviantart.com/liovethisgame/favourites/80375374/sonic-and-korra
-Halo on Fire by "NazoKG"
A fan-made continuation of Nazo Unleashed by "Chakra-X". Taking place 6 Months after his defeat,
Eggman never found his ring like in the post-credits scene, so he goes back to life, and here it is revealed he's really named Enigma, and that he's one of the Chaos Gods. Shadic actually killed Pseudo (his other evil self AKA his split personality embodiment of Negative Chaos Energy) that day, and he's wanted for his crimes as Pseudo back in the Chaos Realm. Shadow and Knuckles find out he survived, and they force him (along with Sonic and Tails) to take them to the Realm due to understandable trust issues. It's still a WIP, but I love what he/she did so far:
https://www.deviantart.com/nazokg/gallery/65381083/halo-on-fire-chapter-1
Happy readings fellows and ladies…