Science Fiction actors who have been in unrelated SF shows

When watching SF shows I often see actors who have been on other SF shows.
I’m talking about unrelated shows, not a SG1/Atlantis crossover.

For example:
Lexa Doig was on Adromeda and Stargate : SG1
and the obvious Ben Bowder and Claudia Black in Farscape and SG1
Jewel Stait was on Firefly and Stargate Atlantis (as a one-off and as different character as a recurring role*)
Christopher judge starts in SG1 and was on Andromeda
Conner Trinear(sp?) was on Enterprise and Atlantis
Jolene Blalock was on Enterprise and SG1
If you consider “Lost” SF, Mira Furlan is in that and Babylon 5
There was actor who was on B5 and DS9 at the same time

Any others? Anybody on 3 unrelated properties? Regular / recurring roles preferred, but one-offs allowed

Brian
*I haven’t seen here in the regular / recurring role, but I have heard about it

Two mentions of B5, and no mention of Walter Koenig, who had a recurring role as Bester on that, but is better known as Chekhov on Star Trek?

D’oh!

And Majel Barret (Roddenberry) did guest on B5 as well as her ST roles.

And Amanda Tapping is attched to “Sanctuary” (as a brunette)

Brian

Jewel Staite was also in an X-Files episode titled “Oubliette.”

If you are counting “Lost,” Daniel Dae Kim was also in the short-lived B5 spinoff, “Crusade.”

Bill Mumy was Will Robinson on Lost in Space, and Lennier on Babylon 5.

Half the cast of Star Trek:THG did voices for the Gargoyles cartoon show (which had robots and was therefore Sci-Fi, the occasional wizard notwithstanding).

And was also a semi-regular in the first season of “Earth: Final Conflict,” which since it was her show based on one of Gene’s old scripts, is not that surprising.

If one stretches and counts “Wonderfalls” then Jewel Staite appeared in several episodes of that as well, as the cute bartender’s hag of a wife.

And “Enterprise” and ST:Voyager. (as different characters, so doesn’t vioalte the crossover prohibition) If you add fantasy he was in “Angel” and “Charmed”

Brian

Patrick Stewart was both Captain Picard and Professor X.

And a regular in “Space Cases”.

His stint was the professor was in the films, as opposed to the TV shows that the OP is requesting.

Michelle Forbes played Ensign Ro in Star Trek: The Next Generation and Admiral Cain in Battlestar Galactica

Stretching the definition of SF just a little, perhaps, but…

Bruce Campbell had a recurring role in Hercules and Xena (as Autolycus), played Brisco on The Adventures of Brisco County, jr, did a voice in two episodes of Megas XLR (a character named Magnanimous, clearly based on him), and appeared in several episodes of Lois and Clark: The New Adventures of Superman. (I think that’s all for his TV SF work.)

I’m having a very hard time picturing Jewel Staite as a “hag”.

Since EW counts Quantum Leap in its top 25 scifi list, I’ll include Scott Bakula. God, is that everyone from Enterprise yet? Dominic Keating was a guest vamp on Buffy once

Not quite. He was in the “Terms of Endearment” episode of The X-Files.

Another X-Files guest star (in “Travelers” and “Agua Mala”) was Darren McGavin, who earlier starred in the short-lived original “Kolchak: The Night Stalker.”

And watching the episode “Demons” I thought the detective who arrested Mulder sounded familiar. It was Jay Acovone, who had been Joe the assistant DA (Catherine’s boss) in Beauty and the Beast (anyone else remember that?). The two shows also shared Howard Gordon as a producer and writer.

“The Secret Room” episode of the cartoon The Secret Show has Tom Baker (the fourth Doctor Who) as a guest voice.

Claudia Black was also in an episode of The Dresden Files

Christopher Eccleston was both Doctor Who and a semi-regular on Heroes

Matt Frewer was in Max Headroom and then guest starred in Star Trek: The Next Generation. He also showed up in Eerie, Indiana and had a recurring part in Eureka.

Frewer was also in that weird X-Files-esque show about the Federal Dept of Scientific Investigation, or whatever it was. PSI Factor, that was it!