If you're looking for manga similar to How to Make a Beta Fall in Love with an Omega Like Me, you might like these titles.
One day the ordinary beta, Nao, reunites with Nagi, an old alpha friend that moved away long ago. This handsome, perfect, princely alpha Nagi has never forgotten the “vow” they exchanged, even as he grew up. And so we find Nao, whose heart races as he finds himself passionately embraced. However, right in the middle of enjoying this reunion, Nao’s body goes through a heat that no beta should experience. It’s an indication that his secondary gender, despite the one in tens of thousands odds, has changed…
Society has discovered that in addition to alphas and betas, some people are born as "omegas." However, omegas face severe discrimination. Abandoned by his parents at birth due to his omega status, Sei grew up in an orphanage, but he escaped as soon as he reached maturity and started living free, like a stray cat, off any man he could find. One day, Sei bumps into a childhood friend he hasn't seen in forever, Yuki Omiyata, a.k.a. Omi. Somehow, this leads to him moving in with Omi! For the first time ever, Sei's living a wholesome life in a stable home. Not only that, Sei realizes Omi's been harboring feelings for him all this time, and finds himself attracted to Omi, too. But, one day, Sei finds out he's got a baby of his own growing inside him...! This spinoff weaves a tale of young love, taking place more than ten years earlier than "The Siesta Mates."
Ren Hoshiai and Yuya Tenmando are childhood friends who are married. The two have an incredibly cute son, Makoto, and every day as a family is filled with sweet happiness, like a dream. However, this is a delicate balance built on the secret that Yuya holds - he's an alpha, not an omega, and the one who gave birth was actually Yuma, Yuya's twin. Happiness and sadness, a new dimension Omegaverse!