Mr. Mime is quite the badass in most of his appearances.
I think we can all agree that at first, Mr. Mime is honestly kind of a weird-looking character, even his name is odd but once you look past that and what he can do in his appearances in the anime, Adventures manga & the movie, he's actually quite the badass and even a scary battler. The most well-known Mr. Mime is arguably Delilah's partner in crime, Mimey. This Mr. Mime along with another manage to build a "reflect"-style cage to put an end to Team Rocket's plans and I have to admit as a kid, I did thought the mime trick was kind of cool. Not to mention Mimey is great at cleaning and maintaining Ash's house, that's pretty badass itself don't you think? Not enough? Then what about the Pokemon Adventures take on Mr. Mime. Sabrina's Mr. Mime is arguably the most well-known from Pokemon Adventures as it pulled off one of the most clever tricks against Bugsy during the Gym Leader Tournament storyline that will make you realize that Mr. Mime is a badass, blowing your mind just how much of a deceptive fighter Mr. Mime can be as he takes so many hits from Scyther and Heracross only to reveal that it was all an act to lure Bugsy's Pokemon into a trap, a two-floored invisible house made of Mr. Mime's reflect move. I was surprised as a kid when seeing that shocking moment and I still am now. It also doesn't help for Bugsy's Pokemon that not only is it difficult to navigate the invisible house but also in how reflect works, Mr. Mime in this situation takes less damage but not Bugsy's Heracross who becomes a sitting target. Now that's what you call a checkmate. And finally there's Mr. Mime of the Detective Pikachu movie. Haven't seen it but already this Mr. Mime is living up to his badassery through the mime interrogation scene from the trailer. I laughed how far Mr. Mime took his mime role seriously including the car cash scene at the end of the trailer.
Well-Known Trainers who caught or befriended the Mr. Mime evolution line.
Mr. Mime - Sabrina (Games, Adventures)
Mr. Mime - Lucian (Games)
Mr. Mime - Valerie (Games, Anime, Adventures)
Mr. Mime - Mina (Games)
Mr. Mime - Delilah, Ash's Mother (Anime) - Caught/Befriended?
Mime Jr. - James (Anime)
Mr. Mime - Emerald (Adventures)
Mr. Mime Full Offensive
Mr. Mime
Item: Assault Vest/Life Orb
Ability: Technician
Nature: Modest Nature (+Sp. Atk, - Atk) or Calm Nature (+Sp.Def, - Atk)
EVs: 252 Sp. Atk/252 HP
Charge Beam
Icy Wind
Focus Blast/Dazzling Gleam
Psyshock
Mr. Mime on full offensive has a lot of potential thanks to Technician which boost weaker moves like Charge Beam and Icy Wind while also maintaining it's effect and that's really about it. It hits hards and tanks defensively on the special side of things. Not so much on physical.
Mr. Mime Physical Sweep Blocker
Mr. Mime
Item: Psychium-Z/Focus Sash
Ability: Filter
Nature: Jolly Nature (+Spe, - Atk)
EVs: 252 HP/252 Spe
Power Split
Thunder Wave
Reflect
Protect/Psychic
Mr. Mime's original role that GameFreak intended was a frail Pokemon with defensive and support capabilities and today, that's still possible despite ironically it's widely considered best sets by the fans are often pure offensive. Mr. Mime is unfortunately very frail and I feel like this was intentional considering how his TCG cards often work as a defensive Pokemon with an Achilles heel. Luckily Mr. Mime has plenty of tools to cover his achilles heel, his low HP and physical defenses. First up is Power Split which can halt almost any Physical Sweeper that isn't relying on stat boosts to a stop, increasing Mr. Mime's bulk potential after Power Split. Even better Psychium-Z boosts speed power so you can setup faster on the next turn, such as reflect or thunder wave. There's also of course Protect and Psychic for further defensive or bruising potential. With Filter and an extra HP investment, Mr. Mime has a better chance of surviving some heavy hitting attacks but just in-case, there's always Focus Sash to get a last-minute support option up.