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
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.
Sources: Lots of research through Smogons competitive dex
I plan to edit this later to include OU and UU Pokemon, as I can't as of right now.