SPOILERS...
Madame Findley was pretty memorable, although I didn't much care for her. Watching her being terrified to death thanks to one very nasty ghost made for interesting watching.
I, too, enjoyed Elizabeth Eis, especially her scenes with both Barnabas and John Yaeger in PT. She made that dreary storyline come to life every time she was featured.
The old guy (Braithewaite as portrayed by the same guy who played Fish?) killed by that very same ghost prior to 1897 also was an interesting character to watch.
Anita Bolster, for sure. She was responsible for one of DS' most infamous bloopers and well-chosen for the role of the white witch trying to cure Barnabas.
The various strumpets--Maudie, et al, made for fun, quickie bullseye characters, as did Donna Friedlander, Carolyn's friend brought in just to be mauled by the werewolf.
Love, Robin