Going back a bit in time, but here are a few more that I believe were slick...

1) Willie Pastrano
2) Joey Giambra
3) Kenny Lane
4) Ralph Dupas
5) Joey Giardello
6) Jeff Chandler

All but Chandler were white- Dupas I think was mixed.

The problem with slick fighters is that as they age they lose a lot of their skills that made them slick and they need to adjust. Most are not power punchers either. Floyd has adjusted well, and so did Giardello who put on a masterful exhibition of that term in 1963 when he beat Dick Tiger, at the age of 33, for the middleweight championship.