Recs if you like Patiently Yours (Fraternizing Omegas #1)...

self explanatory

For my whychoose/reverse harem lovers. No choosing required, you can love them all!

All books on here revolve around non-shifting omegaverse worlds, and the author clearly defines how the omegaverse system works within their book, either at the beginning or end (usually a page or two laying everything out), which makes these books good places to start the trope. * If you read eBooks (at least for Kindle), sometimes you may have to scroll back to get the glossaries since they typically pop up around the title page, and the books usually open to the first page of the book.