Here's a running list of Electrostatic amps our team has used with the CRBN with good success.
Please note: Although the Stax amp listed has the "pro bias" of 580 volts and will work with CRBN, there are some (older) Stax amps that have both the original "Normal" (230 volt bias) and the "Pro" (580 volt bias) sockets. The CRBN requires the use of the 580 volt socket to work properly.
Mjolnir Audio Carbon/Carbon CC
Linear Tube Audio Z10e (also works with regular headphones)
Headamp Blue Hawaii
Maxvalve Headamp 3 MK4
WOO Audio WES
To use with conventional speaker amplifiers to add 580 voltage bias
Woo Audio WEE