Also from the Process Text Group is a Rocket Book Converter. (As well as a Palm Converter.) All of them will convert either a single file or batch conversion from a single directory. (Point of good order: I have purchased many of the converters offered by the Process Text Group and have found them to be of excellent quality.) There are free trial periods offered for all of their converters.
I have updated the MobileRead Wiki page about conversion software
https://wiki.mobileread.com/wiki/E-book_conversion but it is not fully complete (it never will be) however a lot of the main converteres are there.