All the colors makes it hard to read.
I've added a "colorless" duplicate of the list at the bottom, though I think it's the "wall of text" that makes it hard to read, not the colors. (If I could add columns, that would be neat-o.) I think the colorless version is harder to read, but it was easy to do, so I added it.
Relaxed Steelix w/Gyro Ball is an extremely viable option. It can switch into DD Outrages to take very little damage and be able to hit back for STAB + 150 Base = 225 Base, 25 Base short of the power of an Explosion.
That
is quite potent, although Explosion (after you do all the funky halving attack and quartering defense) deals an attack more like 500 BP than 250. Unfortunately, Steelix is definitely not Overused at the moment, so it and its considerations won't make the list. =(
341 - -nature/0IV Steelix (30) (Maxes Gyro Ball power at 150 Base + STAB against opponents with 341 Speed or higher.)
370 - -nature/0IV Bronzong (33) (Maxes Gyro Ball power at 150 Base + STAB against opponents with 370 Speed or higher.)
447 - -nature/0IV Forretress (40) (Maxes Gyro Ball power at 150 Base + STAB against opponents with 447 Speed or higher.)
Hmm! This is highly tempting to add. Although, after thinking about it a while, I realized people would be highly unlikely to
reduce the speed on their pokes to take a little less damage from these pokes in certain situations. It's much more important to outspeed other pokes, and get a complete extra attack in, than to try and have one move from one poke deal 25 or 50 BP less.
Dusknoir comes to mind very quickly. I've even seen Uxie used in it.
I'll add Dusknoir, he seems to be relatively common.
Once the OU tier is nailed down, this list will become specifically OU pokes.
Nice list! This will be really handy to give speed EV's to pokemon. Maybe you can add machamp?
Machamp is definitely not OU, and having 55 speed it can use the same numbers as Blissey, if people are worried about it.