Good call.
A great series, one of the few of hers that I've read, unfortunately. You have to admit, though, that a story that starred the Knnn (don't ask me how many "n's" there are) would not get a lot of readers.
Farscape's aliens, like most movie and TV aliens, are, for the most part, humans in funny shapes. There is a little cultural variation, often less than you see among human cultures.
Once in a while you see something more off the beaten path. The alien in STTNG's episode where Picard is stranded on a planet with an alien who speaks only in metaphors. If I strained, I might come up with a couple more examples from that series. But even the Borg were still humans in funny suits.