1. Moto Hagio
The first member of this illustrious group is Moto Hagio. First off, hats off to her for covering all the bases over her still-active manga career. The woman has made waves with her early shōnen-ai work, The Heart of Thomas, but has also penned evocative sci-fi like They Were Eleven and Otherworld Barbara. Thomas, published in 1974, is an early example of aristocratic boys at a boarding school developing romantic, albeit tragic, feelings for one another. The characters and plotting are soap opera levels of dramatic (as is almost all shōjo manga of the time) making for an emotional marathon read.
2. Riyoko Ikeda
Riyoko Ikeda is likely the only other name on this list to crack into Western anime fans' consciousness. If you aren't familiar with her name, you've at least heard of her most famous work. The Rose of Versailles is a historical fiction piece that would influence other landmark works like Revolutionary Girl Utena, leaving a huge mark on the manga industry itself. The series is credited with pushing publishers to release tankōbon and containing the first implied sex scene in manga. If you enjoy sexy manga fanservice, you can thank Ikeda for that.