I don't know of any master drop-in fitment list for the LokSound Select Direct Micro decoders. However, the dimensions of the 73199 almost exactly match the Atlas "medium" light PCB found in many of their pre-LokSound diesel models like Trainmaster, B23/30/36-7, GP40, etc. I use the Digitrax site's decoder locator and use decoder number DN163A0 to cross-reference what models the 73199 will likely fit in. Be careful, some of the models may still need some frame filing to work, like I found out the hard way trying to install a 73199 into a B23-7. The tops of the frame were too close to the components on top of the decoder and knocked off a resistor. ESU's warranty department thankfully sent me a replacement. There may also be some cases where the contact tabs on the frame will need to be bend downward to make more snug contact with the pads on the decoder.
The 73199 (and 54650 LokPilot) cross-reference to Digitrax DN166I3.