Let me think...
As I spend 99% of my time in WWYD section, thuogh I'm gairly rarely on this site anymore. I have only vague idea what's happening.
How ever, as I look trough scenarios given, and the mamono mentioned in those scenarios, or the ones that give me ability to choose from many.
Warrior beetle. I can't remember a single WWYD scenario giving any real potential for one.
Dark Elf, How ever as I see the character I have hard time writing from her due to the wiki rules, and due to MGE being "overly protective" in some areas.
Raiju, It's bit over the top, so I'm passing it.
Jorou-Gumo it has such negative stigma. I actually like them quite a lot, but again MGE rules kinda stop me writing anything, as I would go "too far" with her.
Girtablilu, But again, I would go too far with them,
Werebat I have used once long long time ago. It's not really that much my thing, but the scenario really enabled me to use her.
I used Gargoyle sometime ago but it was only side characters that got mentioned.
Cu-Sith Cait-sith and Cobold might go bit too "furry" for some, but we barely ever see them.
Ogre is fairly rarely used... Yet again, I would have hard time not going overboard with them.
Kakuen is almost completely absent, even thuogh they are fairly far up on my list.
Orcs, especially high Orcs seem to be fairly rare, but they definitely are one of my favorites, (Try to beat them but fail) But I dont see them that much.
Scylla... I havn't seen a single scenario that would enable one. I have made couple such scenrios, and on replys other got 0 answers, other got 1 and avoided the possibility of a scylla. and that was what... 2 or 3 years ago.
I also used Kraken, but that got really, really bad, reply,