Kino. It took them 13 years to make a second album, and while Radio Voltaire only came out 3 years ago, I still would like to see them make a third album, but I'm sure both John Mitchell and Pete Trewavas are pretty busy with their own stuff to find time to work on another album together.
The Fringe. This trio of Nick D'Virgilio, Jonas Reingold, and Randy McStine was a powerhouse, and I think a second album after their 2016 debut would be great, but like Kino, I assume all three members are busy with their own projects, especially now that McStine Minnemann has been around and released two albums within 7 months.
Star One. This one might actually happen now that Arjen has hinted at working on new material for a third Star One album, but it's still unclear if he will get back all four of original vocalists he worked with on the first two albums, but we can only hope.
Spock's Beard. Not that they've announced a hiatus or anything, but things have been VERY quiet since their last album/tour cycle, and none of the band members have said much about reconvening for a new album. Ryo has been busy with his own project in Japan, and Dave/Ted have been busy with Pattern-Seeking Animals and working on their third album. That just leaves Al, who probably holds the wheel to the ship that is Spock's Beard, and I think if he doesn't feel like bringing the band back together, they may not, especially with half of the band working in PSA now. If their 2018 album, Noise Floor, was to be their final album, I think I'd be okay with it (because I really did enjoy it), but if they're throwing in the towel, I'd rather know sooner than later.
I'm sure there are a few more I could think of, but those are the only ones I could come up with off the top of my head.
-Marc.