As a middle-schooler, I hated most of the falsetto voices (Phillip Bailey, Russell Thomkins, etc) that I later came to love.
Bobby DeBarge was an exception. His was so effortless and there was no ceiling to his upper register.
As an adult, alongside him, my personal faves are:
Marvin Gaye. Of all of them, he got the most nuanced depth of emotion out of his, IMO. He’d switch back and forth out of falsetto into baritone and tenor seamlessly.
O’Kelly Isley. I thought the voice I was hearing on many of my favorite Isley Brothers ballads was Ronald (another great) but it was his big brother. Kelly’s was a bit more finely-detailed, understated, fluid and developed.
Sananda Maitreya aka Terence Trent D’Arby. The guy is SERIOUSLY underrated as a singer, songwriter, musician and performer. He’s got three voices he uses. First there’s his distinctive raspy baritone/tenor, then there’s something between a growl and a roar and then…a falsetto that can go from angelically weightless to a raging scream.