Lopunny's main role in the competitive scene is just its Mega Evolution. However, if you're opting for not mega evolving it, its stats are mediocre at best. However, with Klutz, it is able to ignore the effects of its held item. Although that sounds terrible, its not as terrible when you discover Lopunny has access to Switcheroo. Lopunny has an decent support movepool, ranging from Baton Pass, Encore, Healing Wish, Thunder Wave, Toxic, Sweet Kiss, Heal Bell, Substitute, Magic Coat, and more.
So perhaps something like this:
Lopunny (F) @ Choice Scarf
Ability: Klutz
EVs: 248 HP / 8 Def / 252 Spe
Jolly Nature
- Switcheroo
- Encore
- Toxic / Thunder Wave
- Healing Wish / Heal Bell / Attaking move
Switcheroo gives the opponent the Choice Scarf without affecting your Lopunny at all due to Klutz. Encore can lock Pokemon into a support / weak move. Toxic / Thunder Wave cripples the opposing team further, while the last move is for more team support, or some attacking move so Lopunny doesn't become total Taunt bait. Attacking moves can be High Jump Kick, Drain Punch, and Return / Frustration. Whatever floats your boat.
If you desire a more offensive Lopunny, however, (with that glorious 76 Atk), then you can opt for:
Lopunny (F) @ Life Orb
Ability: Limber
EVs: 252 Atk / 4 SpD / 252 Spe
Happiness: 0
Jolly Nature
- Fake Out
- High Jump Kick
- Frustration
- Ice Punch
This attempts to make use of the the nice movepool that Lopunny receives. Fake Out is for priority, as well as chip damage. High Jump Kick has great power, and takes down the Steel and Rock Pokemon that attempt to wall its Normal STAB. Frustration is used over Return in case of the rare Ditto, and offers a good powered stab move. Finally, the last moveslot can really be customized to your liking, as Lopunny as Ice Punch, Thunder Punch, Fire Punch, Iron Tail, Work Up. Most people will opt for Ice Punch as it provides the most coverage, but it really depends on what you need.