Honestly, I just went back to 'Blue Blur, Broken Heart' after seeing it pop up again. It's got a weird hold on me. It's this surprisingly grim take on Sonic dealing with the aftermath of losing someone in the Freedom Fighter days, but it's not just angsty misery—there's a lot of quiet, awkward rebuilding with Tails and Amy that feels earned. The prose can get a bit purple sometimes, but the author knows how to write Sonic's restlessness in a way that isn't just him being a jerk. It’s more about him not knowing how to stop moving, which, yeah. Kind of fits.
There's another one that’s the complete opposite mood-wise called 'Chaos Control for Dummies' that’s basically a sitcom. Shadow tries to teach Silver how to use chaos control for mundane stuff, like making perfect toast or getting the last cookie from a high shelf, and it spirals into Team Dark becoming a dysfunctional family unit. The dialogue is snappy and it doesn’t take itself seriously at all, which is a nice palate cleanser after heavier stuff.
Also, don’t sleep on the 'Sonic Underground' tag if you're into deeper cuts. There’s a ongoing fic there that reimagines the trio reuniting as adults, and it deals with the political fallout of being royalty in a world that’s moved on. It’s got a slower build, but the world-building is genuinely impressive. I keep checking for updates.