This topic kind of confuzzles me, as I thought tiers were determined by usage...whatever. Anyway, I think Toxicroak should be moved up to BL... it's very unpredictable and has great offense. I used this Toxicroak which wrecked quite a bit of havoc:
Toxicroak @ Leftovers
Dry Skin
Modest/Rash
4 HP
252 SA
252 Spd
Nasty Plot
Focus Blast
Hidden Power Flying
Sucker Punch
Dry Skin is great for absorbing water moves and compliments Rain Dance fairly well. Sucker Punch is great for stopping sweepers and taking out Gengars/Starmies (though I don't think it's a OHKO), and a Focus Blast after a Nasty Plot does around 78% to Blissey. It's nice to be able to switch on Machamp or Heracross and HP Fly them to death.
Of course, there's many other variations, such as Sub/FPunch/SPunch, Swords Dance versions, Choice Band versions...
I must agree there. Toxicroak has such viable sets, and has got an above average attack stat + SD to help it along. Coupled with the fact that it can learn Cross Chop and has the Dry Skin ability, it makes for a really worthwhile Pokémon in whichever tier you play it in.
Also, another few I think are viable enough for BL play are the Hitmons.
I have never worked out why they aren't included in the BL tier.
Lets take a look at Hitmontop first.
I'll be using the Technician set for my example -
Hitmontop@Life Orb (Life Orb gives a 30% increase, as i'm sure you know.)
Adamant (+Attack, -SpAtk) - 252 HP/252 Atk/4 Spd
Fake Out - I can't remember the power, does it get an increase by Technician?
Mach Punch - 40 Power, first turn move, 80% increase. 72 Power in the end. Thats great. Along with first turn move....
Close Combat - meh. Power.
Bullet Punch - Another first turn move, and will have the same power as Mach Punch in the end.
So, IMO, its really quite viable.
I'll post the others a bit later.