Zenbu, Ω na Ore no Sei.
I tried to read this one without checking the comments for why it was rated so low, but within the first few chapters, I immediately understood why. This is your typical series about the omegaverse filled with rape and threats then sugarcoated with a forced love relationship in order to include smut. Horrible writing, plain water is more flavorful than this entire cast of characters.
Dear Benjamin 1.5
Are you looking for an omegaverse BL/Yaoi that isn't severely basing the plot on the omegaverse theme? This one fits the bill extremely well. It's a "mystery" romance between two men where their secondary gender isn't the main driving factor of the story, but rather the secrets they want to keep from each other. Art is neat, story is good enough, the baby is cute, one of the few omegaverses that are good so far (up to Ch 15 currently). Pacing seems to be relatively thought out as well.
Secret Note
Mixed feelings about this one. Pacing is slightly faster than it needs to be, but the overall plots hasn't been too bad. Seems ok?
Haga-kun wa Kamaretai
This is pretty predatory which sorta(?) makes sense since it's in prison, but if you look past that factor, this series has big crackhead energy. It's a meme and it's pretty funny.
2ban-me no Alpha
Omegaverse story that doesn't involve rape left and right and an overbearing setting about gender discrimination. Plot is very short, but sweet and real at the same time. Art style is very nice and clean. Deserves the 5/5.
Shinai Naru Omega e
This was an interesting read and left a bittersweet taste. None of the characters are happy, but none of them are unfortunate either. It's entirely up to you to interpret whether there was a happy ending or a sad ending. Warning: possible signs of Stockholm syndrome. Welcome to a twisted yet somehow very tame tale about the omegaverse, where discrimination is, surprise surprise, rampant, and there's sexual implications involved for just existing as an omega. An unfortunate pair meets one obstacle after another and finds a miracle after they resolve a dispute. Yet, this miracle was still not entirely a miracle.
Oboreru Omega