I've divided the list by ryona and gyaku ryona animes; some contains both so I put them where I think they have more of.
Ryona
Higurashi No Naku Koro Ni (Horror anime, the first season (this one) is very gore-heavy; the male protagonist is also sometimes the victim; if you want to make sense of the story you have to watch the second season, too)
Witchblade (Women/girls turn into superhumans with "armor" that either doesn't cover certain areas or looks like a skin-tight suit and battle it out; also one of the few animes that does not only shows off their protagonists' bosoms but also their asses)
Freezing (High-school romance in a world you could describe as females being warriors/tanks and males being wizards/priests; expect a lot of bitch fights. Properly THE ryona anime but it somehow left me bored)
Hyakka Ryouran Samurai Girls (I was hyped for this anime by
this but apparently master samurais fight by shooting projectiles with their blades or turning into energy balls and bump into each other instead of fighting in melee range... found it extremely boring but may you guys thing otherwise)
Gyaku Ryona
Basilisk (Ninja anime; some females have some cool abilities, like sucking blood through skin contact or emitting poison when sexually aroused; I quite enjoyed watching them doing so; not sure how much it offers in terms of "normal" ryona )
Bokusatsu Tenshi Dokuro-chan (A comedy about a boy and an angel who constantly throws a fit and decapitates the boy and such only to revive him a few seconds later)
Baka to Test to Shoukanjuu (Slice of life high-school comedy; especially during the first few episodes one girl often does wrestling moves and holds on the protagonist, including a tag-team F4-leglock plus armbar.)
Bakemonogatari (Strange mystery anime; the protagonist is badly manhandled a few times; also one or two "normal" ryona scenes, like constriction by a snake)
Kore wa Zombie Desuka? (It's about the high-school worries of a cross-dressing magical girl zombie; yeap, it's as crazy as it sounds; the protagonist is kind of immortal and thus often badly beaten up; also has a lot of pegging-related jokes)
I just notice how many animes use the (kind of) immortality of their male main protagonist to kill them off over and over again.