Find: Limited Moon, Save Crystal, 2 Guard Sources, 1 Mind Source, 1 Magic Source, 1 Elixir, & HP Absorb Materia.

If you get back in the airship and head to Cosmo Canyon with Red XII in your party, go see Bugenhagen. He gives Red XIII the Limited Moon, his ultimate weapon. Then he dies and now you return to the crater.

Climb down the ladder to the ground. Walk down to the next screen. When Cloud says that you have to slide down, say the first option. Run left to the chest. It has a Save Crystal. This item is only usable once, but it makes a save point where you use it. My suggestion is to use it at the meeting place later on. You can also enter the cave to exit the crater.

Spiral around counter-clockwise, jumping over the pits as you go. The next chest has a Guard Source. Keep going all the way down. On the next screen, run to the right and climb down to the chest. It contains a Guard Source. Run down around to the right to get a Mind Source. Jump down and either continue on or go left and get the rest of the stuff.

If you go left, climb up a couple ledges and get the chest on the far right. In it is a Magic Source. Climb some more and get the Elixir from the chest. Go up and left to the chest for a Power Source, then run right on the same ledge, behind the rock, to get an HP Absorb Materia. You can climb out of the crater here.

Climb back down to the bottom and exit. The next screen has many caves. You can learn the Enemy Skills Laser and Dragon Force here, from the Dark Dragons. Also, learn Magic Breath and L5 Death from the Parasites if you haven't learned them yet. Walk off the first ledge, then walk right and fall to the chest below. Get the Mind Source. Go to the end of the ledge and jump up to the next ledge. Run left and fall to the next ledge. Run right and enter the cave.

Get the Megalixir from the chest inside. Exit again and run to the left until you fall. Get the Hero Drink from the chest and enter the hole. Go around to the chest for a Guard Source. Run up into the hole and circle around for a Power Source, then exit. You are now at the first ledge again. Run to the right to fall, then enter the hole. Follow the path and exit. Now fall left, then right, then left twice to exit.

Climb down to your friends. Take one of the paths. Each path will give you different items, but you will end up in the same place.