So I'm currently creating an adventure that involves a Human/Hill Dwarf city (by the way, this isn't set in the Forgotten Realms, it's a homebrew universe) with a corrupt Hill Dwarf mayor that is paying some monstrous humanoid creatures on the side to act as goons that none of the city's inhabitants are aware of. The party will of course have to fight these goons and expose the corrupt mayor at some point, but for this question I'm more interested in flavour rather than balance (i.e. it doesn't matter what CR they are vs. the PC's level).
I was wondering what creature (from the Monster Manual or Volo's Guide, the latter of which I don't have at the moment but will do by the time I run this adventure), ideally an evil humanoid race like Orcs, Hobgoblins or Bugbears, would be the most likely to work for money like this?
I'd like to keep to more monstrous creatures as opposed to humans or dwarves since I want the adventure's enemies to be more varied and unusual, and secondly because I want their presence to raise questions in my player's head (i.e. "What on earth are they doing in the city? Who is behind this?") as a clue to pin this all on the mayor. Also, there are a few sneaky human assassins (i.e. "hiding in plain sight" enemies) and dwarven bodyguards that are more "public", so I wanted to have a third kind of enemy that serves as some behind-the-scenes muscle doing the dirty work.
Off the top of my head, I seem to remember Bugbears being appropriate (according to the Monster Manual description), but they feature heavily in our current adventure, so I'm reluctant to reuse them, so for variety, are there any other such creatures that would be appropriate? I suppose answers could be subject to opinion, so it would be best to back up any speculation with quotes from the Monster Manual or Volo's Guide or something similar so that the answers can be SE appropriate.
Despite the fact that this isn't set in the Forgotten Realms, I'm happy to for answers to keep to the lore of known publishes universes such as Forgotten Realms, etc; for example, I read somewhere that Hobgoblins apparently hate Elves especially, so it's a good thing this is a Human/Dwarf city because if it were an Elven city that would make Hobgoblins a really bad choice, etc. - general details like these can be assumed to be true of my homebrew universe as well (obviously this question can't be answered at all if this homebrew universe changes everything completely since only I could possibly know what creatures would fit).