No eroge novels (aka 'erotic visual novels') in this list: there are so many of them that we have made a page just for them.
We also have a page for Adult interactive Fiction for smut made by non-Japanese writers.
You play as a cute young woman who can transform and get different costumes and abilities by "magicking" certain objects, like swords, bows, brooms, etc.
Not much to do besides kill some monsters and A community-made spiritual successor to Hentai High School.
There is also a worthy sequel, and the finale released.
Freeware Metroidvania game where you play as a young girl named Marie, trying to escape from a facility full of spikes and killer laser robots. ) that will protect her from hazards but gets torn off in the process, leaving her topless, bottomless or completely naked.
The game is very difficult, but provides infinite quicksaves and has very tight controls; as a bonus Marie's current level of nudity is reflected in cutscenes and the ending, so you're rewarded for playing dangerously.
You are a new principle at a failing school, and make it your personal mission to corrupt the students, PTA, and entire city.
You can employ anything from charisma to blackmail to optional hypnotism.