Kakko Warukute Kakkoii Kimi
This is so cute. Childhood friends get to high school, and then one starts to pull away from the other! He's upset about something ridiculous (his height) and eventually everything works out.
Rutta To Kodama
Roommates who fall in love and continue to be in love and say "I love you" for about 20 chapters. No sad, all happy. This is nice to return to if you're having a bad day, and you can dive in anywhere once you've read it. A nice pick-me-up!
Yandere Hitotsu Yane no Shita
A PWP with nice art and a sweet, dense main character who doesn't realize his male roommate - who cooks, cleans, and has sex with him - is interested in him. Normally I wouldn't support a boyfriend installing surveillance equipment on his lover's phone, but in this case I'm not sure Yano would live through a day otherwise. The second story is about a front desk clerk who considers turning down his dream of being transferred back to to the main Tokyo branch because years ago, he messed around with the manager. At a friend's bar, a man spots his business partner's son dressed as a young woman.
Ouji No Hakoniwa
1) After his parents' business goes bankrupt, a young man turns to crime after they're forced to leave their family home. Years later and estranged from his parents, he returns to the house under the pretense of visiting his former butler with the real motive of robbery. But the butler has no intention of letting him leave. 2) Shuu actively ignores his roommate Chitose, an insatiable playboy famous for his habit of sleeping with any woman on campus named Aki. Only Shuu understands the cruel reason: it was Chitose's nickname for him, a misreading of his name, but Shuu forbid him from saying it after they slept together and quietly suffers jealousy. This is no "how to" guide for how to land a boyfriend, but it's an entertaining read.
Hitorijime Theory
A collection of stories about a series of couples. This is the one with the guys who had lived together for two years and even slept in the same bed before they ever hooked up.
Wonderful Days?
Two stories involving roommates. The first pair falls for each other; the second is a love triangle.
Yuuhi ni Fureru Sono Mae ni
Read this for the first story. The other two are quite short, but the first - two roommates falling in love across seasons - is lovely.
Spicy & Sugary