Low-sec / null-sec ratting
In low-sec systems, 0.2 and below, you can find BS rats with bounties up to 1M ISKs and decent loot, and some cruisers with those expensive tags inside. Hunting these NPCs can get you some fair incomes, if done properly.

There will be two kinds of ratting fleets:
PvP ready and just sneak.

1. Sneak fleets
These kind of fleet will be composed by a main ship, usually a bc or, less often, a cruiser, fitted so that it can escape camps and small gangs (fittings will be shown only in corp), and by a small group of frigates acting as support for scouting and helping to kill the NPCs.
This fleets are not meant to PvP, so they will disengage if attacked by non-NPCs.

2. PvP-Ready fleets
The name is self-explanatory: these fleets will hunt rats but will be able to defend themselves should the need arise. For obvious reasons, compositions is not shown here :)