There was a 1e supplement... I'm 87.33333% sure, but if so I've misplaced it. And then there is Supplement 2 from Classic Traveller. In both cases (one, perhaps part of some odd fever dream?) it is a listing of encounter tables based on world and terrain types.
Which is probably not how to do a future book, but now that you ask, perhaps the method for creating such tables is a part of a future book, and who doesn't love a spreadsheet with some dropdowns and RAND functions to create them on the fly (except I don't think you can create a seeded value without VBA and macros always set off the virus alerts... so they would need to be pasted as values to stick...).
And add a bunch of example species and add some 3I invasive species to a catalogue section and... Bob's your uncle? (except, my one uncle was named Finn, and Bob is the name of the armless, legless, stone cat that guards our driveway [Bob would sink, spoiling the joke, but still..] )