As it happens, I'm about three episodes away from finishing ReGenesis. I watched it in inside out order (third season, then fourth season, then first season, and then second) which is not a bad way to do it especially since it goes a wee bit completely bonkers at the very very end.
Off the top of my head -- besides Mayko as a regular -- Patrick Garrow (Turin) is in a couple of episodes in season 3, Rob Stewart is in a couple of episodes in season 4, Weej can be spotted in the background in a season 4 episode, I'm pretty sure I saw Sean Baek in there somewhere, but I don't remember which season.
And going the other way, the dude that plays Bob in ReGenesis is almost unrecognizable as Coren the heavily bearded Space Pirate from Killjoys season 1 who was Dutch and Johnny's pre-credit's warrant right at the beginning of the first episode and then showed up at least one other time.
Edited March 21, 2019 by yrnamehereleft out one of my favs and also to fix wall of text
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