If you have a different answer depending on the game (Paper Mario 64 or Thousand Year Door for this poll) you may pick 1 from each if you'd like!
From right to left for those who need a refresher:
Top Row: Madame Flurrie, 
(But he don't count), Parakerry, Kooper
Middle Row: Koops, Vivian, Goombella, Lakilester, Goombario, Lady Bow
Bottom Row: Admiral Bobbery, Ms. Mowz, Yoshi, Watt, Sushie, Bombette
spoiler
No surprise that
is in the lead. She's definitely one of the more unique designs (and not based on a Mario enemy, I think?)