Alright, I'm not super great at competitive, and I only play National Dex, but as this question hasn't been (properly) answered for nearly 3 years, I'll try to do my best
Ubers
The only Electric type ranked in Ubers currently is Zekrom, though keep in mind Regieleki, Magnezone, and Galvantula are occasionally used, as Regieleki is often a physical attacker, Galvantula is a Sticky Web setter, and Magnezone is a good Special Attacker, I'll only be talking about Pokemon ranked at Ubers to save time, but I'll bring up Pokemon occasionally used
Zekrom is a great wallbreaker in the current metagame, being equipped with really good STAB, and having Dragon Dance. Increasing its great Attack stat, and giving it good speed. If Zekrom lacks its speed boost, it gets out-speed by the common Dragon and Fairy types that roam the metagame, and has problems handling Pokemon with Choice Scarfs like Ditto, Kyogre, Calyrex-S, and Yveltal
Now Water types are a different story... Palkia, Kyogre, and Dracovish are ranked at Ubers, and Gastrodon, Toxapex, Cloyster, and Quagsire are occasionally used. Cloyster is a Spike setter with Shell Smash, Quagsire is a Unaware Wall, Toxapex is a Toxic Spikes setter, and Gastrodon is a Toxic User that threatens Kyogre from what I know.
Kyogre is a great Special Attacker, with 150 Sp. Atk and the ability Drizzle increasing it's Water STAB's power, and even being able to run an accurate Thunder. Despite its low speed, it can be equipped with a Choice Scarf to out-speed common wallbreakers and make quick work with them, or given a different item so it can run Calm Mind. Kyogre has a hard time dealing with common dragon types like Eternatus, rarely seen grass types like Zarude, is walled by Blissey, and the rain they set has a hard time to deal with Thunder.
Palkia's great STAB type and coverage for practically every type allows it to check Kyogre with Thunder while also managing to deal with the common walls in Ubers. Palkia's a great check to Kyogre due to getting a nice STAB boost from the rain, and its Thunder's always being accurate in the rain for use to try to get paralysis. Palkia however doesn't get anymore defensive utility, as making Pokemon burnt or paralyzed is what it relys on, and is outclasses by Eternatus, Palkia can hit everything neutrally, but is difficult to try to make it able to 2HKO its foes.
Dracovish is a sweeping beast! Fishious Rend is a great move, having STAB, a Strong Jaw boost, and Double damage if it out-speeds, and as I've mention before, Water/Dragon has some great STAB potential. Due to it's mediocre speed stat, it's seen having Choice Scarfes, and occasionally Choice Bands. Dracovish has some alright coverage, being able to deal with it's weaknesses. Though, Dracovish has problems dealing with Freeze-Dry Kyurem-White, and the fairy types in the metagame.
OU
Now, there's more than one electric type mon in OU, in fact, there's five! These Pokemon consist Magnezone, Tapu Koko, Zapdos, Zeraora, and Regieleki! Arctozolt, Dracozolt, and Thundurus are ranked in UUBL, but I won't be talking about Pokemon in those tiers to save time.
Magnezone's a pretty good special attacker and support, having pretty good abilities, but somewhat-mediocre coverage that still works out in its favor. The ability Magnezone is often seen being used would be Magnet Pull, to trap the Steel type Pokemon that roam the tier, such as the likes of Corviknight, Skarmory, and Ferrothorn. Magnezone's drawback is that it's 4x weakness to ground makes it have a hard time running either Air Balloon or Leftovers.
Tapu Koko is a great pivot user in OU due to its high speed and its good offensive and defensive type. With access to recover through Roost, it helps making it easy to counter Pokemon that it's strong against. It helps with teams needing help with speedy Pokemon with good offense. With limited coverage however, allows it to get walled by the tiers bulky mons. It also has meh defensives, so most attacks will bring it at below half health, forcing it to pivot out with Volt Switch or heal back out with Roost.
Zapdos's defensive typing and its ability Static allows it to check and punish offensive threats often used in the metagame, such as Kartana and Rillaboom. Additionally, it can also check common U-Turn users like Landorus Therian and Rapid Strike Urshifu. Its often used in rain teams as it can check the Grass types mentioned, as well as infinite accuracy Thunder/Hurricane, as well as Water type Weather Ball allowing it to deal with Heatran more effectively. However, Zapdos has trouble being used over Thundurus Therian and Tornadus Therian which are more faster and can break through defensive walls. Zapdos also has trouble with handling Toxic and is forced to run Heavy Duty-Boots due to Stealth Rock damage, as well as having competition with Skarmory and Corviknight which have better defensive typings.
Zeraora is one of the best offensive pivots in the OU metagame due to its access to Knock Off and Close Combat as well as its high Speed, allowing it to threaten most of the Pokemon viable in OU. Due to its high Speed, it can also revenge kill the likes of Weavile, Tornadus Therian, as well as Dragapult and as a Volt Switch absorber due to its ability Volt Absorb, allowing him to fight off other Electric types like Tapu Koko and Zapdos. However, Zeraora is very frail, which results in it being unable to switch into attacks, unlike the previously mentioned Electric types.
Regieleki is a very good suicide lead due to its 200 base speed, as well as access to Rapid Spin in order to clear hazards for its team. However, Regieleki can't absorb hits very well due to its defensive stats (80/50/50), and access to 0 form of recovery, meaning that other leads may be able to defeat it before it can setup both Reflect and Light Screen. Its movepool is extremely barren too, resulting in its Choice Specs variant to be forced to use Ancient Power.
Sources: Lots of research through Smogons competitive dex, and a bit of personal experience
I plan to edit this later to finish this and include the Pokemon I haven't included yet, as I can't right now.
