Zeraora is ok. Nothing spectacular, but not as terrible as I thought it'd be.
So a few sets that I've been toying with:
Zeraora @ Focus Sash
Ability: Volt Absorb
EVs: 252 Atk / 4 Def / 252 Spe
Jolly Nature
- Plasma Fists
- Endeavor
- Quick Attack
- Taunt
This has been doing pretty well at stopping sweeps, removing Scarf Lando, or simply whittling fat mons down for another teammate. Taunt stops recovery, Endeavor brings said mon to 1 HP, then it gets taken out by Quick Attack. I like to pair this with a Pursuit-trapper so that if Zeraora goes down, the whittled mon can't escape.
Here's an example of what this set can do:
https://replay.pokemonshowdown.com/gen7ou-770449778
Zeraora @ Life Orb
Ability: Volt Absorb
EVs: 252 Atk / 64 SpA / 192 Spe
Naive Nature
- Plasma Fists
- Close Combat
- Hidden Power [Ice]
- Work Up
Mixed Work Up. +1 HP Ice has the strength to OHKO offensive Zygarde from full and most HP invested sets after a small amount of chip. +1 Close Combat also OHKOes Ferrothorn, Tyranitar, and Heatran. Speed is to outpace Mega Lop and Modest Alakazam, and the rest goes to Attack and Special Attack.
This replay isn't particularly great, but it demonstrates how strong this can be at +1:
https://replay.pokemonshowdown.com/gen7ou-770460698
This mon has serious issues, though. It's very weak without setup, Chose Band, or Z moves. A Life Orb unboosted Close Combat can't OHKO Kyurem-Black without rocks, and unboosted Plasma Fists fails to 2HKO Clef:
252 Atk Life Orb Zeraora Close Combat vs. 0 HP / 0 Def Kyurem-Black: 307-361 (78.5 - 92.3%) -- guaranteed 2HKO
252 Atk Life Orb Zeraora Plasma Fists vs. 252 HP / 252+ Def Clefable: 168-199 (42.6 - 50.5%) -- guaranteed 3HKO after Leftovers recovery
It's also practically hard checked by Mega Alakazam, a mon rising in usage as of late, thanks to it Tracing Volt Absorb. Zeraora also doesn't like the usage of Scarf Lando-T being so high now that other mons are setting up rocks like Clef and Heatran. Not having access to U-turn is also a serious bummer, whereas Tapu Koko, the superior Electric-type, has it. Choice Band would have loved U-turn, but alas. It checks most Koko sets that don't opt for Dazzling Gleam, but U-turn chip is annoying to deal with.
If there are a few benefits to running Zeraora compared to Tapu Koko, it's that it outpaces Ash-Greninja and Mega Lopunny, has Close Combat and Fire Punch to deal with Ferrothorn, has access to Knock Off, and has a slightly stronger Hidden Power Ice. Otherwise, just use Tapu Koko.
Edit: Here's what I've been using for Choice Band:
Zeraora @ Choice Band
Ability: Volt Absorb
EVs: 252 Atk / 64 Def / 192 Spe
Jolly Nature
- Plasma Fists
- Close Combat
- Fire Punch
- Knock Off / Hidden Power Ice
Fire Punch OHKOes Kartana (Close Combat does also), OHKOs Ferrothorn after rocks, 2HKOes Mega Scizor, Amoonguss, and Tapu Bulu, and 2HKOes AV Tangrowth after rocks. Close Combat is for Tyranitar, Heatran, Excadrill, and Chansey while being your best neutral attack for Grounds like Hippowdon and Zygarde. Knock Off is able to 2HKO the Mega Latis and defensive Mew. Knock Off is also nice for removing the Leftovers from various Pokemon to wear them down for Zeraora later, such as Clefable and bulkier Zygarde sets. HP Ice, meanwhile, 2HKOes any form of Landorus-T even with a Jolly nature, and does slightly more damage to Zygarde than CC.
From my experience, Toxic Spikes support works very well with this set. Pokemon like Zygarde, Tapu Bulu, Tangrowth don't appreciate the constant residual damage from Poison as they come in on Banded attacks.
Replay:
https://replay.pokemonshowdown.com/gen7ou-770597340 Toxic Spikes put pressure on Tangrowth later on in the match while Zeraora's Banded Plasma Fists puts Clefable in range of Mega Latios's Psychic.