First, a list of pokemon who should utterly obliterate it given a standard non-boosting set or a great coverage move:
Counters:
Rhyperior
Tyranitar
Steelix
Blissey
Snorlax
Regice
Cresselia
These pokemon are either generally bulky enough to survive two or three hits in a row from Draco Meteor/Thunderbolt, and can either hit for super-effective damage, phaze out, utilize reliable recovery, or in general stop a sweep cold. Rhyperior is the most suspect but since it is usually played in a Sandstorm environment it is in truth much less so.
Checks:
There are infinitely more checks than there are hard counters. Electric/Dragon is particularly vulnerable to revenge killing from any of the above and the following:
Dugtrio
Salamence
Latias
Flygon
Heatran
Mamoswine
Hippowdon
Weavile
Swampert (Swampert is not listed above because it lacks reliable recovery and cannot boost its SDef via Sandstorm)
Now all these checks and counters only take into consideration Electric and Dragon attack moves. Surf/Hydro Pump eliminate a significant portion of the Ground type counters and Tyranitar to an extent, whereas Flamethrower/Fire Blast/Overheat eliminate Steelix and Regice specifically. Magnet Rise makes slower ground types unreliable revenge killers or even counters, since their best alternate recourse tends to be low-powered Ice moves or Hidden Power.
There are more pokemon that situationally counter, such as HP Ice Magnezone that switches into Draco Meteor, but generally speaking Zone is slower, both its STABs are resisted (Tbolt 4x), and since CAP8 is faster it will win in an SE HP vs. SE HP war.