Z87 OC Formula 1.90
ASRock > Z87 OC Formula
Z87 OC Formula/ac 1.80
ASRock > Z87 OC Formula/ac
Fatal1ty Z87 Professional 1.70
ASRock > Fatal1ty Z87 Professional
Z87 Extreme4 2.40
ftp://europe.asrock.com/bios/1150/Z87 Extreme4(2.40)ROM.zip
Z87 Extreme3 2.20
ASRock > Z87 Extreme3
Edit:
More releases.......
http://www.asrock.com/support/download.asp?cat=BIOS