That's Second Most in WNBA, After UConn(Schools Listed Here)

SkinsHoops86 had a couple of tweets on this, which I'll cut and paste:

UConn - 19
Notre Dame - 9 (If Jess had recovered in time that would've been 10)
Maryland - 7
Duke - 6
Tennessee - 6
Louisville - 5
Rutgers - 5
South Carolina - 5

"26 of the 65 Power 5 schools don't have an alum on a WNBA roster. That's 40%. Some of the good mid majors provide just as good of a path to the pros, if not better, since these kids probably got to be key players early in their careers and were on winning teams." - SkinsHoops86

Non P5 schools (minus UConn - already listed) with WNBA players:
Middle Tennessee State - 2
Princeton - 2
Delaware - 1
DePaul - 1
George Washington - 1
Georgetown - 1
Gonzaga - 1
Marquette - 1
Saint Joseph's - 1
South Florida - 1
Temple - 1
UTEP - 1