Piracy team compositions change depending on variables, such as group size, what we're hunting, whether we're active hunting or snaring, the current patch trade meta, etc..  The Mantis and Cutlass Blue are often the backbone of a pirate group.

Pirates tend to favor ships with speed such as the F8C, Buccaneer, Warlock, Hawk or F7 series.

Ships with decent speed and heavy damage output like the Inferno or Ion also have their uses.

Logistics ships that have cargo bays, med bays, salvage and/or refueling capabilities are also useful.

Again, this depends on the situation but having at least 2 QED ships, a specialty DPS ship like an Inferno or Ion, a couple of scouts and some regular fighters is a good start.

In groups larger than five, 1-2 fighters for overwatch and scouting can be helpful.  QED is the backbone of the pirate fleet.