Lopunny's biggest asset is her unpredictability, as she can run a large number of sets effectively. When Lopunny's revealed, you won't know whether she's a supporter, a Baton Passer, or maybe even both. Many opponents blindly switch in the Pokemon who would be least effected by Switcheroo, but this plan can go awry if she sets up Substitute or Agility. Lopunny can always manage to keep her opponents guessing.
Although unpredictable, Lopunny faces stiff competition from Alakazam and Jumpluff, who both have access to Encore as well as higher Speed. Alakazam can employ Trick as well, and Jumpluff has a crippling Sleep Powder. With Trick being so widespread, other Pokemon are chosen instead of Lopunny for this particular role. That being said, Lopunny still has one the largest support movepools of any Pokemon (including the excellent Baton Pass) and a unique ability which distinguishes her from other Trick users. Lopunny's strengths lie not in brute force, but in support and messing with the opponent's strategy. One misprediction can cost you the match, so underestimate her at your peril.
High Speed coupled with Encore is a dangerous combination, especially when the user can also employ a quick SubPass strategy. This is arguably Lopunny's most effective set, as it combines all of her assets and abuses them to the fullest.
Lopunny works as a simple Substitute passer, allowing frail teammates to get in safely or on an attack they otherwise wouldn't be able to switch in on. Encore is Lopunny's greatest tool in making sure the strategy is pulled off. Lopunny can Encore weak attacks or an attack her teammate is immune to, and then simply Baton Pass and allow it to obtain a free turn. Switcheroo is an excellent move to round out this set. Because of Lopunny's unique ability, Klutz, she can simply bide her time and choose the appropriate Pokemon to cripple, unlike other Trick users such as Uxie and Mesprit who would be forced into one move. Klutz also allows her to absorb the harmful items an opposing Tricker may try to cripple one of your Pokemon with, and throw it back at the opponent. Flame Orb is a great option to cripple powerful physical attackers who enjoy switching into Lopunny, such as Rhyperior, but Choice Scarf cripples a wider variety of Pokemon by locking them into one move.Team Options & Additional Comments >>>
With base 105 Speed and access to Encore, Lopunny makes a brilliant Baton Passer. Unlike Lopunny's other sets, this set takes a less subtle approach in setting up her teammates, and is particularly risky, but the payoff can be huge.
The plan is to switch into a Pokemon who is using a support move such as Stealth Rock or is healing itself and Encore the opponent, locking it into the last used move. You can also abuse Lopunny's immunity to Ghost by switching into Shadow Ball or Shadow Sneak. Once Encored, the opponent will likely switch, giving Lopunny an opportunity to use Agility. At this point, begin using Substitute as the opponent attacks you. After the third Substitute, the Berry you've chosen will kick in, and the boosts can be passed to a sweeper who will obliterate the opposing team.Team Options & Additional Comments >>>
Lopunny's support movepool is nearly unmatched, making her a fantastic choice to aid the team. Switcheroo is perfect to cripple Lopunny's common switch-ins. Ground-types such as Torterra and Fighting-types such as Hitmontop will be rendered useless by Flame Orb, which cuts their offensive capabilities significantly. Choice Scarf cripples walls and sweepers by locking them into one move. Encore allows Lopunny to halt set-up attempts and gives her team free switch-in opportunities. For example, Lopunny can Encore weak attacks from Registeel and go to a threatening sweeper, giving it a vital free turn without fear of status. Heal Bell gets rid of all status effects on your team, while Lopunny can spread status herself with Thunder Wave. Employing a dry Baton Pass is a great strategy to help build momentum and safely counter threats, although if Taunt is troublesome Lopunny can run Return which packs enough of a bite to hurt frail sweepers significantly.Team Options & Additional Comments >>>
Lopunny has an extremely large support movepool. Toxic, Charm, Captivate, Mirror Coat, Fake Tears, and Swagger are all options that weren't mentioned but can find their way into a specialized set. Lopunny can be a decent weather supporter with the proper item, high Speed, and access to both Rain Dance and Sunny Day. Fake Out and Quick Attack can be used on Lopunny, but Ambipom is better in that department. Endeavor is available and can be used to severely weaken a Pokemon as Lopunny's health becomes low.
Although it's not one of Lopunny's strong suits, she can run a few viable offensive sets. Lopunny has access to nifty physical moves such as Low Kick and the elemental punches, making a Choice Band set a decent option. She can also still utilize Switcheroo; just don't forget to use Cute Charm. In addition, Lopunny can run a SubPunch set as her common switch-ins such as Steelix or Rhyperior are weak to Fighting, and she can Baton Pass the Substitute to a more capable Pokemon if the need arises.
Checks and Counters
Since Lopunny's sets are geared towards support, a mixed attacker such as Blaziken, Nidoking, or Sharpedo makes a great initial switch-in. None of them mind any of the Choice items and can hit Lopunny hard with the proper attack. Fighting-types including Hitmonlee and Hitmontop can OHKO Lopunny with their STAB attacks but they don't enjoy receiving a Flame Orb or Choice Specs. Hariyama can obtain a Guts boost from Flame Orb or Thunder Wave and OHKO her with STAB Close Combat. Arcanine can hit Lopunny hard with Flare Blitz and heal off any damage with Morning Sun, while also being immune to Flame Orb's effects. He won't particularly enjoy a Choice Scarf or paralysis, however. Faster Taunters such as Ambipom and Floatzel shut most Lopunny down, as do faster Encore users such as Alakazam and Jumpluff. Steelix, Donphan, and Blastoise can ruin any attempts at Baton Passing with Roar while Altaria can accomplish the same with Perish Song. Haze Milotic can switch in and remove any boosts Lopunny may have attained.
Countering Lopunny is a daunting prospect because she will always manage to cripple at least one Pokemon, or pull off at least one successful pass. It may take multiple Pokemon to scout her set, but once it's revealed she shouldn't cause many problems. Just don't forget that her access to Encore means that pulling off a sweep will be difficult until she's eliminated from the match. Luckily, she has no way of healing herself and is worn down quickly.