How does one deal with sleep? well that depends on what’s sleeping you. Here are some possible panacea’s as well as lesser options that generally are good for most threats.
Full Stop: Espeon, though I am not sure on the set. Espeon has great speed and special attack combination (and obviously supercritical ability) but figuring out the best set isn’t something I’ve really tested that much. I’ve tried a dual screen set and now I’m going to try a choice specs set: Psycho Break/Cold Flare/Thunder/Aeroblast (because I hate MH users, and Choice Specs Cold Flare 2HKOs max HP/Special Defense Sableye). Concerning cold flare: on PO it is a one turn move essentially letting you use Ice-type draco meteor without special attack drops so you can use it as Ice STAB on nonice pokemon. In addition, Espeon can be combined with other special sweepers and act as a pretty decent butterfly dance passer. You can try assist power as well but it’ll take two butterfly dances before it gets superstrong. Also you can try Xatu as an alternative, which is a bit bulkier on the physical side.
However, the most common sleep move is spore and there generally is no incentive to use a different one. Herbivore users can eat spore and gain +1 attack, which in some cases is better than magic mirror because of lum berry. Also an attack boost instantly contributes to your ability to sweep.
Adamant Nature (+Atk, -SAtk)
Stantler appears to be pretty good, but we are so early in the testing we're not sure. Yes, Stantler’s stats suck, but its stats are apparently good enough to be redeemed with Herbivore. With +3 Attack you have a very good chance to OHKO Skarmary with Sacred Fire after SR as well as is a guaranteed OHKO on 0/0 groudon. Meanwhile, not much else is going to survive STAB Extremespeed. Even if you get taunted (which is uncommon on most sporers) the enemy will still have to deal with decently powered STAB ES and your other moves. No speed EVs because after a shell smash you won’t need any. Shadow sneak deals with Gengar if you need to know. Thank jc104 for this. Miltank and Girafarig are alternatives. There are also fifth gen pokes with better stats but they don’t have mimic glitch.
You can also try vital spirit pokemon but my opinion is that they suck but maybe, maaaybe Primeape can be of some use. But I am not going to give a strong recommendation at all. Anyway here it is courtesy of theotherdoug:
Going Ape Hog Wild
Primeape @ Life Orb/ Focus Sash/ Salac Berry
Ability: Vital Spirit
-Belly Drum/ Shell Smash
-Close Combat/ Drain Punch/ Reversal
-Shadow Force/ Crunch
-Extreme Speed/ Mach Punch/
Switch into the sleeping moves that will no doubt be all the Rage in this Meta-game, set up Belly Drum/Shell Break, and let the sweeping begin!
If you're using Shell Smash then a Focus Sash and Reversal are better options; otherwise go with Close Combat/Drain Punch and Life Orb/Salac Berry.
Choose either Shadow Force or Crunch to hit those pesky ghosts; Crunch will provide a reliable no-draw-back attack. Meanwhile Shadow Force not only hits harder, but it might lure in a fast Normal or Steel type, whom you can greet with a Mach Punch next turn.
For priority you can use Extreme Speed, Mach Punch as I mentioned earlier, or Sucker Punch to hit Ghosts immune to E.S. and M.P.
These are very important because Sableye or any other 4th gen mystery heart user will use a sleep move to priority sleep you. To make it even more ridiculous this can be combined with taunt which prevents you from sleeptalking. If you aren’t going to use primeape or stantler and your opponent uses one of these the only thing you can do is spam Lum berry, that’ll stop them cold especially when combined with a team of hard hitters. Remember nothing in street pokemon even with legality out is unbeatable, just some things are ridiculous powerful (and how powerful here is debatable), it’ll never be like Mewtwo in RBY and definitely not Lugia in GSC, we can’t be bothered to stall all day.
Other sleep spammers are easier to deal with. You don’t need lum (or at least not like you did before), you can just use something like sleeptalk shuckle and while sleeptalk isn’t reliable when combined with the right moves you come out on top more often than not. For example I like to run:
Whirlwind/Sleeptalk/Roost/Spikes on my shuckle. Just get something that can ruin a fast pokemon’s day, especially Ninjask. Because if you’re not Gengar/Mewtwo level fast or faster, chances are you are not spamming sleep everywhere. Quick reminder: Gear change Skarmory (which is common by skarm standards) does use spore and Mewtwo has been absent from the metagame lately, which kind of puzzles me.