Kashikomarimashita, Destiny
This starts as your typical alpha/omega "I'm going to fight my nature!" story between two young heirs, but that's just the setup to the true love story between the two butlers. It centers around the concepts of destiny and choice, because one butler is a beta and will never be his mate's fated person. I'd put off reading this for months and finally devoured it on a weekend morning. It's lovely, touching, romantic, and extremely satisfying by the end. Plus the art is beautiful.
Nandaka Ii Nioi
Two stories: teachers who date and one has a scent fetish, and neighbors who have been friends since childhood. One visited the other often because he was too sick to go out. Now that he's relatively healthy, he works full-time while the other is still in high school. Because they'd known each other for so many years, the age gap didn't bug me too much, but I think it was probably 16 - 21-ish? Maybe older?
Ore no Itoshi no Neet-kun
Two stories: Childhood friends who finally confess their longtime mutual love. One can't hold down a job and is always taken care of by the other. After they're together, he deals with premature ejaculation and is a hilarious character who gets lots in his fantasies a lot. The second story is about a boy who is seen hugging a friend's jacket by a frightening classmate, who turns out to be a warm and supportive friend (and maybe future boyfriend). Open ending.
Mizuiro to Pinku, Sore kara Daidai
The best story in here was the oneshot about the man whose mother had warned him against a haunted house - to find later it was inhabited by prostitutes. I wanted to know more about him and the man he'd started to see. There was also a sickly childhood friend who had recovered and come home; I wanted to know if their relationship ever got off the ground, what happened with the distance college had put between them. Neither is developed past the initial groundwork.
Himitsu no Love Sensation
Lovers become coworkers and have to navigate new hurdles. They also help a gay student in love with his friend. Spin-off from Family Simulation.
Itsuka Tomodachi Ja Nakunaru To Shite Mo
HI I'M CRYING! This is absolutely lovely. Tomo and Shuuhei have been friends since childhood, when one was injured during an accident that took the sight in one eye. Tomo has been in love with Shuuhei since high school, content to stay with him as a friend. But when he kisses a seemingly sleeping Shuuhei, his feelings are exposed, and Shuuhei has to examine his own. Features an incredibly welcoming and lovely family. Marked incomplete but the love story is done. Maybe there are extras?
Soba Ni Oitene
two stories in one! childhood friends who have pretty much always been in love (and are really open about it) and two high school friends who end up living together
Shiranai Kao