I did some research on the Supplemental Draft, primarily from my library of old Ourlad's and Kiper's Guides. There have been 35 players selected in total and 8 first round picks have been used with Dave Brown being the latest in 1992.
Since 1990 there have been 14 selections:
Rob Moore WR NY Jets 1990
Willie Williams TE Phoenix 1990
Dave Brown QB NY Giants 1992
Darren Mickell DE Kansas City 1992
Tito Wooten DB NY Giants 1994
John Davis TE Dallas 1994
Darren Benson DE Dallas 1995
Mike Wahle OG Green Bay 1998
Jamal Williams DT San Diego 1998
D'Juan Cherry DB New England 1999
Milford Brown OG Houston 2002
Tony Hollings RB Houston 2003
Manuel Wright DT Miami 2005
Ahmad Brooks LB Cincinnati 2006
Regarding the eight Number 1's used by position:
QB- Dave Wilson, Bernie Kosar, Steve Walsh, Timm Rosenbach, Dave Brown
RB- Bobby Humphrey
WR- Rob Moore
LB- The Boz
Memories, anyone?