The Indecency of Delta ~Princess Is A Pupil of Sin~ Trainer type, but with additional gameplay elements. Very nice pixel art, lolis (but with this graphic it didn't bother me, even though I don't usually play games with them). There are 3 games in this series, and there are more games by this author. I personally liked
False Myth nice combat mechanic, dating sim, not bad plot, cute characters. The only thing I didn't like it's that we play for girl who genderbent into a man (but she remained her girl face), other than that it's nice game.
Cosmic Abduction - Heroine Natsuki is suddenly abducted by mysterious aliens, and taken to a far-away planet. Mostly revolves around sex with some interesting minigames that well integrated with adult theme of the game. Very good pixel art and animations. I can also recommend previous game of this dev -
Queen's Legacy. It's a platformer, prostitution, pixel art.
If you're not afraid of NTR:
Leane 2: Leane of Legitimate Crown. Country Conquest Style Strategic Fantasy Simulation. You control heroines and armies and conquering the world for your king (bad guy, who will want to add your generals to his harem). The story a bit nonsensical, at least the premise involving the main character (I will not reveal the details, to avoid spoiling your judgment), but the gameplay is very nice and NTR is avoidable if you play your cards right. Main character also have some time with girls if he deepens his bonds with them, but obviously the amount of vanilla content here is sparse. Not animated.
I could go on scratching my head, but here is another idea. Have you tried the Gacha games from Nutaku? Not all of them are that bad and require money investment. My personal favorites are Kamihime Project, very large cast of characters, somewhat decent story, all girls are voiced and have various skills, accompanied by beautiful visual effects during combat. It's one of the games that treats fre2play users very fairly. Content with heroines is easy to unlock. Animated.
Another game is Magicami DX. I can't say that I played it much because I'm not that into magical girls, but three of the things that stood out to me were: The art and animation, it's just amazing, I've seen very few examples of this level of quality in both hentai and adult games. Second is the soundtrack, it's very good and you can tell the developers put a lot of effort into it. Third, despite the Japanese love for magical girls, the plot is somewhat serious and sometimes even dark. I really liked the character design, and unlike other gacha games, there are not thousands of characters, but a rather smaller cast of girls, which IMO is a plus, as it gives the opportunity to unfold these heroines properly.
