I posted an idea on there too:
I'd like to see something most people don't really think all that much about: Ice. Oxygen and Hydrogen are important for all kinds of chemical reactions, and water itself is important for life. Every time a ship leaves a station, the crew probably takes a bit more water than they left behind and that creates a deficit. Stations import ice for their hydroponics and for breaking into oxygen to add to breathable air. Ships need the hydrogen component to fuel their engines. And if you think about it, space stations aren't closed systems. Whenever a ship leaves and gets destroyed, that's some water and air you don't get back. Being able to transport big chunks of ice would allow these to be refilled. In addition, biological material gets trapped in ice and preserved, so scientists might pay a tonne for ice samples from new planets, especially if there was a mechanic for "coring" properly, to see the layers of ice corresponding to ice ages and thaw points during that planet's history. Particularly pure ice could be a luxury on some planets, featuring "Exotic Spring Water from imported for your delight! Only 1500UEC!" On top of all this, it could create interested variations of cargo game-play, having to keep it frozen.