As of August 2023, the new KX-200 is the only radio intended as a direct, slide-in replacement for the legacy KX-155/165 radios.  At one time, TKM Avionics intended to produce and market their MX-155 radio. However, this Arizona based company, went out of business several years ago. 

Garmin offers their GNC-255 line of nav/comms.  However, it is a new installation as it uses different rack & connectors and is different in size.