Alright, if you guys need crystal and such and you need a bonus to what your already getting here's my suggestion, two actually.
1. Find a planet that has no alliance and has been inactive for 7 or more days. (Their names are greyed out and have a lower case or uppercase "i" on them.) They should have resources free for the taking but to be sure always send a probe in before hand. If your espionage level is at least 2 or 3 you will get a report on their defense, if they have one. If no report on defense comes out they are like ripe apples ready to be picked and you'll know exactly how much materials they have. I've pillaged at least 50,000 crystal and metal using this method.
2. You can research your expedition technology and go on fun deep space expeditions. How? All you need is your fleet and the appropriate coordinates which are as follows Any Galaxy: Any System: 16. Those coordinates will send your fleet on an expedition where they can find many things. I've confiscated about the same amount of crystal and metal but I've also found free ships like light fighters, cargoes, and even a recycler. But according to the stats you can find any ship and bring it back besides the deathstar. So I'm constantly going on expeditions and expanding my fleet for free.
So if you ultimately need resources use one of those two methods to help you out. If you need someone who's been inactive "weakened" call on Vay or I and we should have a force capable of destroying their defenses.
[EDIT] Strike that, due to my copius amounts of resources left over the rank 19 person in the galaxy is attacking my main planet. I can only assume that all my defensive structures are to be obliterated and that all my minerals are going to plundered. I took steps in showing that there is no point in attacking me for profit as I dumped all my possible minerals into cargoes and shipped them away and used the rest on research and defensive structures. We'll see how the battle turns out but I can only assume I'm going to be set back at least 100 steps.