I use a custom column (Mstr Format: #master) with a Fixed list of values.
Code:
Multi,RAR(Html),EPUB,HTML(zip),RTF,KF8,Mobi,ODT,PDB,LRF,PRC,DOC,PDF,RAR,Other,BAD,TXT,LIT
The order is funky as I usually type the first letter. (Multi means I downloaded more than 1 format from the publisher. Archives list the content format. YMMV
Unfortunately, setting this is a Manual operation