I recommend
VOLVOX/o.p com works. All of them are vanilla and some sort of comedic elements, the bad thing is some doujins have a lot of text bubble, the good thing is all of his works are in a shared universe and has a fantasy/sci-fi element too.
- the strict student council president gets sexual stress relief from MC. The plot twist she's half elf/human addicted to sex.
- MC and heroine are from the same art club and she likes to do body paint on herself and be a exibicionist. The council president makes an appearance.
- MC got in a car accident in the middle of a florest because he was looking for a secret village and meets an "onee-san" Kunoichi who is specializes in scents. MC is the only one who can endure her afrodisiac scents. This ninja woman is the older sister of the Kunoichi from the previous work and this MC is the older brother of the previous MC.
- MC is a good guy, but has a delinquent face. So he was mistaken for a criminal by an undercover agent discuise a next door neighbor, who uses her body to arrest him. At the end, she finds out the real culprid but still have sex with MC. The older sister ninja and older brother MC are mentioning as a couple from the same appartment complex.
- The heroine is a reincarnation of a ancient warrior, now she the ace of athletic team and a sprinter. She's infamous for have sex with a lot of guys and drains their stamina. MC is a bookworm that helps her with ancient history and the only person who can endure her. There are cameo from the student council president and delinquent face MC.
- The MC got hit by a car and after wakes up notices everyone has a number above their head and this number is related to sex. He starts to hook up with a famous gravure idol and finds out she's a sex addict. There're cameo from the Kunoichi couple and the female doctor, the sprinter and that MC, the body paint couple.
- A meterite hits a countryside place where MC and his childhood friend lives. MC meets and an adult, succesfull and beautiful woman and starts to have sex with her with his CF watching. The childhood friend gets in the action too. Later is revealed that the childhood friend and the adult woman are the same person. The childhood friend goes back in time (as adult) and have sex with MC to prevent him from get killed by a meteorite, the childhood friend is a science genius.
- MC when he was a kid he got drowned, that let him have a trauma that unables him from swim and getting a girlfriend, so he works as a delivery guy in the summer until he goes to a mansion and starts to have sex with a misterious woman who reveails to be a succubus and she was the one who saved him in the past, but put a curse on him that make the girls avoid him. The president council makes a cameo.
EDIT: I removed "Kunoechi!" and "Let Me Use Your Body" doujins because I notice they violate one of the rules of hentai section.