You have a ship, you have a crew, you have guns. But what then? Nobody's gets far as a freelancer without a job. While carrying cargo such as water from Novus to Gilgamesh is a rather easy and safe job, it's not worth much and the monotony hardly is what most freelancers are looking for.
Freelancers commonly take more illicit if not outright illegal jobs. Both on the ground and in space. And complications are expected at all turns, especially when the client doesn't want to pay or the law is watching.
Freelancers are also different from pirate that they usually work jobs and crime is not always their designed target. Most freelancers are moral people and generally would not resort to attacking civilian ships for pillage.
Illegal Salvage is when a ship pillage a wreck that belongs to a government or one of Liberty's mega corporation. While civilian ships are legal, they rarely carry the same amount of goods or the same value as a destroyed Valiance Cruiser or a XenoCorp Cargo. More often than not, the goods are also marked and so need who doesn't mind buying hot goods.
Heists are still popular, whether it's stealing from a Cargo ship, a planetary transport or a secure facility, the goods are there and people are ready to pay for them. Many governments or corporations are also ready to hire deniable assets to get the booty for them.
Seek and Destroy are exactly what it says, most freelancing ships are equipped enough to handle a fight and bounties can be a good source of revenue. And short of sustained plasma fire, few things can damage a ship's black box, which is all that's required to capture most bounties, although the most lucrative will require live captures.
Deliveries are probably the second oldest job, right behind prostitution. As soon as someone invented point A and point B, people were needed to get stuff between the two and jobs requiring things that are illegal or that needs to enter quietly are often good and easy money.
Diversion are an example of a job where the freelancers have little to do with the actual jobs, but sometimes someone is needed to distract the homeguard while the mule slips by with the shipment of illegal goods or that someone infiltrate the normally secure compound.
Smuggling is one of the simplest but most lucrative job. When something is outlawed, demand usually remain but supply dries up. Whether it's drugs, weapons or luxury goods, people want it. Then there's the alternative smuggling perfectly legal goods as to avoid paying taxes and duties on them.
Passenger Ferrying is more of a side bonus to make some money, when a bunk is free in a ship, the captain can always get a few extra bucks by renting the bed or cabin for a one way trip. Although the verse is not a stranger to large quantities of refugees camping in someone's cargo hold, especially those wanted to get away from colonies or Valiance.