The D&D 5e Basic Rules PDF includes a list of eight consultants whose opinions and expertise on RPGs were valued enough by Wizards of the Coast to get them involved in the development of the newest edition. This list displays a wide range of approaches to the hobby and many different philosophies towards game design. Some are more obscure than others, but each has proven their RPG design chops.
Jeff Grubb - An RPG veteran, his credits includes Marvel Super Heroes (FASERIP), Spelljammer and The Manual of the Planes. He's also an accomplished author of novels, short fiction and comic books.
Kenneth Hite - The RPG hobby's high priest of horror and the occult. His many writing credits include Nephilim, GURPS, Vampire: The Dark Ages, and Trail of Cthulhu.
Kevin Kulp - A game designer whose newest project is TimeWatch, an investigative time travel RPG using the GUMSHOE system.
Robin Laws - A game designer and novelist who has had a hand in developing some of the most innovative games on the market. He has designed games such as Feng Shui, Hillfolk, Over The Edge, and many of the games using the GUMSHOE system.
S. John Ross - The designer of Risus and Uresia: Grave of Heaven, among many other games. One of those games is the Pokethulhu Adventure Game, which is probably the greatest accomplishment on this list.
RPGPundit - The designer of Arrows of Indra, Lords of Olympus and the Dark Albion fantasy setting. He created the theRPGsite.com forum and regularly blogs with his opinions on RPGs and other subjects.
Vincent Venturella - Founder of Venture Land Games and the creator of the Narrative Game System.
Zak S. - A vocal proponent of DIY D&D. He is the author of Vornheim, a sourcebook for running urban crawls and building cities. His forthcoming A Red and Pleasant Land is his take on adventuring in Wonderland. He actively blogs at Playing D&D With Pornstars.