Basically Zekrom with Fly.
With Dragon Type and electric type moves Zekrom has great coverage spare Ferrothorn, Exadrill, Magnezone and Steelix. However for the latter three Zekrom has only two options Rock smash or focus blast, both are iffy at best, Ferrothorn on the other Hand can be dealt with through fly, ferrothorn will likely be the new forretress, so it will be pretty common. Fly provides Zekrom with a way around this. also Zekrom sports a rare 4x resistance to thunder so even it the rain, it flies safely.
PS Smogon lists ferrothorn as one of zekroms counters so this would be even more viable.

Zekrom
Jolly / Adamant
252 AT 252 SP/HP 6 HP/SP
Outrage/Dragon Claw
Bolt strike/Fusion Bolt
Fly
Some other Move/ Dragon Tail/ Volt Change/ Etc

besides the fact that It give the opponent a chance to switch out, which I see as the biggest threat to this set what other comments do you have on it?

I already have a good reshiram set I'm looking for a good zekrom set

Fly allows Ferrothorn the opportunity to switch out. Best bet would be to run Naive or Hasty nature and use Hidden Power Fire. Zekrom has 120 base Special Attack which is more than enough to take things on with it.

Zekrom @ Life Orb
Naive nature
252 Spd/208 Atk/48 Sp Atk
- Dragon Claw (or coverage move)
- Outrage
- Hidden Power Fire
- Fusion Bolt

QFT, barring HP fire your probably better off with Rock smash if your goal is just to beat Ferrothorn and hate focus blast. It Hits in one turn, 10 less power than fly and has a 50% def drop rate which makes switching risky. But if you use Bolt strike you'll be doing more with it resisted anyways. A Hasty/Navie nature w/ Focus blast is probably your best choice if you can risk the accuracy.

I may be wrong on this but Teravolt doesn't stop Iron barbs from damaging (In gen IV Mold breaker didn't block rough skin) so that's another reason to use focus blast.