Before people ask why I put tails on the same tier as knuckles and rouge, I will say that tails has beaten multiple enemies who have scaled to knuckles, (tails is physically strong but knuckles can punch the ground and cause an eruption, so yes, for the record I know knuckles is physically way stronger than pretty much every other character). Regardless however, I think Tails' mobility, flight, iq, and speed makes up for his shortcomings in strength compared to knuckles. Rivals 2 he fights metal and rouge to a stand still, and the same for battle. (She even said that tails would give her trouble in a fight)

​

And for the record, Im not trying to over exaggerated a characters strengthor anything. Tails is my favorite but I would never try to boost him up just because of it. But, looking at the obscure side games, (which believe it or not were actually the last games in which the characters got developed), tails did this stuff.

​

Also knuckles and amy could probably be moved up a tier, and if you want to count light gaia when he unleashes his power then move him up as well.