From this list...

Yztargs
Belladonnas (Morta)
Snapweeds
Twitherym
Chapulis
Craklaws
Pteraketos (Bismarck)
Ovim (rams)
Lucerewe (sheep)
Tulfaires
Leafkin
Kulox (Apian Beasts, I believe)
Botuli
Harpeia
Most are, however Yztarg, Apian Beasts, Belladonna, Pteraketos, Harpia, Botuli, and a few others related to them but not actually in the list are all from before Adoulin. In fact, Yztarg and Apian Beasts were first introduced through Meeble Burrows, which was out probably a year or so before Adoulin's release I think, while Belladonna, Pteraketos, Harpia, and Botuli, as well as Gallu, Mantid, and Naraka were all introduced via VW. The Snapweeds, Twitherym, Chapulis, Craklaws, Tulfaires, and Leafkin are all of Adoulin origin though. Matamata are also from Adoulin and aren't mentioned though they are Lizards, which have been released, as well as Heartwings. If you include alternate skins as new monsters, there are the new Orange Sheep & Rams that are listed, the Ovim and Lucerewe, but then there are also the new bunnies which were with Adoulin, the Lapinion, as well as the new Red Behemoth skin, Ruby Raptors, Red Mantid, and possibly more, though that'ss all that comes to mind right now.

Now, here's where inconsistency comes in and why I somewhat hesitate to include alternate skins in this list. While we lack the Red Behemoth, Ovim, and Lucerewe, we actually have access to Lapinion and Ruby Raptor skins. We also have some Adoulin and Meeble specific skins or entire monsters such as Panopts which originally came from Meeble Burrows just like Yztarg and Apian Beasts, they are now in Adoulin as well, and yet we have this race but not the others.

All in all though, some of those are VW, others Meebles, and a few Adoulin, but it's spread out, and the fact we have other monsters like Panopt and Lapinion kinda shoots a hole in the 'It's because it's from Adoulin/Expansions' theory because even while VW requires WotG at least and Adoulin requires, well, Adoulin, Meeble Burrows requires nothing, and yet there are a couple mobs in Meebles that we've yet to see in Monstrosity.