Yes there are a handful of custom single missions, though no campaign. Back when I was the mod lead I did make a mission that was going to serve as a first campaign mission, and that mission is completed and a part of the mod files along with a handful of other missions other folks made.
So its just the missions included in the OT mod at the moment. Got it. Though Im surprised no one freded in new custom missions in for the OT mod for its existance. Maybe i should give it a try?
I may also suggest this topic or future questions be directed torward the OT mod topic page on the ‘Release’ sub forum.
Should I repost this then over there?
A few people did make missions but those were included in subsequent releases of the OT mod. I think a few people have made some missions for themselves, and the current people working on the OT mod may have more insights!
Feel free to add some of your own to and submit them to the current mod devs, the more missions the better I would say.
I think you might find other similarly minded people with that avenue. I know that the current devs have also stated they want to release the OT mod on Knossos at some point too, so perhaps you can talk with them about adding any missions you make into the Knossos release.
Here is the link if you want it:https://www.hard-light.net/forums/index.php?topic=85153.0