Find nothing. Find an Alien Virus, though nothing comes of this. Find some small "Pets", though nothing comes of this. Find Dark Matter. Find resources, but only as much as your fleet has cargo space for. Find a merchant from an alien world to trade with. Gain ships. Find an alien/pirate fleet and be attacked. A combat report is made. Find Solar Wind or a wormhole. Your fleet returns sooner. Get lost. It will take your fleet longer to return. Get lost, your whole fleet will never return.
The wiki / Google is your friend.