There is a whole forum dedicated to TWA file archives:
viewforum.php?f=39and there is the TWA Database Project:
http://microblaster.net/TWAs.aspxYou download these TWAs and then import them from the command center. The archive files can include alien names and ranks, and ANSI files, but designers rarelt took the time to do ANSI, and I do not know if any of the archives include ANSI. Alien names and ranks were often put in the common game folder, so they often get left out of the archives. Some archives included post scripts to rename class 0 ports and make a variety of other changes post bang, but these scripts are not included in the TWA.
Almost all TWAs are pre-anniversary edition, so you will need to set delays, Interactive sub-prompts, and check all the settings when importing.