Benchmark has Slew Rate of 16V/uS.
HK receiver has a slew rate of 40V/uS.
Parasound Halo has a slew rate of 130V/uS.
http://www.parasound.com/a23.php
Mark Levinson did not list any slew rate either, although it's probably the same as ATI (50-60V/uS) - also Monolith, Outlaw, Cary Audio, etc.
Bryston listed the slew rate at 60V/uS.
Anthem amps' slew rate is 30V/uS.
https://www.anthemav.com/products-current/type=amplifier/model=mca-225/page=specs
Krell - slew rate = 40V/uS.
http://www.krellonline.com/stereo-amps.html#Duo125
McIntosh, PASS, NAD, Rotel, ADCOM, Emotiva, Crown, QSC, Yamaha, Marantz, Denon - no slew rate listed.