Prog keyboardists not named Rick, Tony or Keith

Although I can see that Devon-born Robin Lumley is already mentioned on one of the lists, not dedicating an entire post to him would be an omission. Namely, Lumley, who sadly passed away last year, alongside Phil Collins, was co-founder of one of the most significant jazz-rock bands ever, Brand X. He took a sabbatical from the band in 1978 to focus on his career as a record producer, but he returned for the Brand X final albums and tours in the early 1980s. He also produced albums for Bill Bruford and Rod Argent (with the latter, Lumley even formed a jazz-rock band in the early 80s). 

Here's a majestic live recording from the 1976 John Peel show that included Brand X's original lineup featuring the late Robin Lumley.