No I know there are other pokemon but a lot of people slap assault vests on rather mindlessly and ignore the rather large tradeoffs that come as a result. Meloetta is one of the best pokemon suited for it because it doesn't have any killer recovery moves that it will miss out on, it doesn't have nasty plot or swords dance so it rarely tries to set up, and it relies on serene grace to deal effects instead of status moves. Meloetta hates being choiced because a vast part of it's appeal is that it simultaneously can function in two ways that require different counters, and life orb reduces it's survivability. Sure missing out on leftovers is never fun, but it's a pretty good tradeoff for being a psychic type that can negate it's weakness to it's common weaknesses (ghost and dark) through typing and prediction.Plat There are actually multiple pokemon who can effectively run an Assault Vest set. I am currently in love with using Entei, and I am also wanting to try out other users of it such as Slowbro, Metagross, maybe even AV Zapdos or Mienshao could be cool. When it comes to Assault Vest, your horizons are almost endless.
Meloetta is also a pretty great counter to Mega Houndoom:
252 SpA Solar Power Mega Houndoom Dark Pulse vs. 252 HP / 4 SpD Assault Vest Meloetta in Sun: 222-264 (54.9 - 65.3%)
252 SpA Solar Power Mega Houndoom Fire Blast vs. 252 HP / 4 SpD Assault Vest Meloetta in Sun: 229-271 (56.6 - 67%) -- guaranteed 2HKO
Which means Meloetta is guaranteed to get the relic song off, outspeed the next turn and demolish with close combat.
0- Atk Meloetta-P Close Combat vs. 4 HP / 0 Def Mega Houndoom: 314-372 (107.5 - 127.3%) -- guaranteed OHKO
Even if Mega houndoom carries sucker punch, it is only doing around 9-11% to a timid Meloetta-p.