Authorize.net is a credit card merchant gateway.
BluePay is a credit card merchant gateway.
eProcessingNetwork is a credit card merchant gateway that uses the Authorize.net SIM Emulator integration.
Forte is a payment gateway module in WHMCS.
The IP.Pay payment gateway module is available in WHMCS.
LinkPoint (First Data Global Gateway) was a payment gateway in WHMCS.
Merchant Partners is a credit card merchant gateway that is integrated with WHMCS.