Battletech 2025 Mech List. Here is a link to a list of all 4,202 official mech variants. I have been working on a full list of mechs (since the online spreadsheet has not been updated for 1.9) which indicates the base game mechs for campaign scoring and the sdlf mechs with.
This page lists all ‘mechs currently found in game. Here is a link to a list of all 4,202 official mech variants.