Quota
A mode based around Cargo or Science trying to pump out enough shit to appease Nanotrasen, keeping them from shutting down the station. Shutting down means "You signed a waiver, so we're just going to blow the station up with bluespace artillery, or maybe even leave you to rot!".
Quite simply, send X amount of rare materials & experimental equipment to centcomm. Raw materials could do the job but you'd have to mine half the asteroid for that, but whatever. More developed stuff like R&D Xray rifles or say BIG STOMPY MECHS would bring in the dosh. Things that the station shipped out with wouldn't count for your points, and might even give you negative points for trying to trick centcomm, you'd have to actually show you're producing stuff.
Pretty much, the more complex, the higher the value.
For extra
!!FUN!! you could have random antag slots. You could have the chance to have no antags, and the station just focusing on X with all the mishaps that may happen, like meteors and power failures and whatnot, to dealing with several traitors and lings attempting to keep you from meeting the station's quota.
Patriarch & Matriarch
Think a combination between Changeling & Blob/Xeno. Although, it would be changelings.
Changelings are these weird alien creatures that eat people right? They can morph into whoever, and fuck your day up. But what if the changelings we all know and love (or hate) is just their infancy stage?
But where do these fuckers come from? How are they made? Are they science experiments, or some natural phenomena from some hellish sector of space?
Imagine, a good ol' fashion horrorfest, where the changeling is much more developed, and much more deadly. You would come aboard as a more developed changeling, ready to molt into your next step of evolution. The catch is that there would be only one, maybe two if you were in a high pop round. Your objectives are a lot less about stealing and sneaking, and much more along the line of making this station a fancy buffet for you and your kin.
You'd start out as a "Pariah", thing a ling that has eaten dozens of people, and adapted to be much stronger than your average changeling. You'd decide if you want to be a Patriarch, or a Matriach.
Patriarch would play somewhat like changeling, but more along the goon variety, you would eat and gain more powerful abilities as you go on, with the ability to shed your human form and turn into some hulking fleshy monstrosity. This would be a lot less about sneaking about, and a lot more about ambushing and eviscerating. You're a monster, ready to fuck people's days up, sort of like a Blobbernaut but smarter, and therefore much more deadly.
Matriarch, however, would be somewhat like a mix between being a Blob & an Alien Queen.
You would hunker down and become some sort of hideous bio-reactor hivemind, corrupting the station and creating headslug-crab-things.
There would be mobile and immobile stages - in mobile, after you've shed your human form, you would be able to create your minions and consume corpses, just basic stuff because you don't have a lot invested in your nest at the time, but upon anchoring, with which you make the commitment to mold into your surroundings and become a full fledged bio-reactor matriarch, you would have access to a much more RTS orientated perspective.
You would have basic units controlled by yourself in a Blob-like perspective, who you could send out through vents to go fuck somebody's day up, and bring them back to consume or convert. Consuming would give you more bio-matter to play around with for various thing.
Bio matter would regenerate over time, like ling chemicals, and you could use it to create new basic units & structures - Blockages and whatnot that would be really hard to destroy, Gas pumps to make an area spew toxic miasma (Effectively blocking the area off from the unprepared, you would need a hardsuit or bio suit to really get through these areas), and various other countering defensive growths that would help you in the long run.
Conversion, however, would make a corpse into a lesser changeling. Think an armbladed husk thats sole purpose is to defend the matriarch. These would be how changelings come to be, through this form of reproduction. You wouldn't, of course, turn into a regular ling after some time, you would just be a lesser ling without the ability to revive and whatnot, just a few abilities like a lesser form of fleshmend and your blades and whatnot. This would bring people back into the round and make Matriarch lings less of a annoying fuckfest to deal with, less people calling bullshit, more people having fun, but this would also be a double edged sword - if you saw lesser lings, you'd know that the matriarch has anchored down, so it's a matter of search and destroy for the crew at that point. If the matriarch dies, all the lesser, hivemind linked lings, would die as well. This would only apply to the ones THEY have created, in case there's two matriarchs aboard (70+ pop rounds)