Where in the Crater are Malboros?
Where in the Crater are Pollensaltas?
Where in the Crater are Dragon Zombies?
Is there any way to get Trine after I have already beaten Gaea’s Cliff?
All three are around the “Dragon Skeleton” looking area. When you have to go up or down at the first branching point, head up. If you enter the area with 2 more branching paths, go back. The area looks fiery, has bones all over, and plays the “Ancient Forest” music known as “Chasing the Black Caped Man.” The other areas play the North Cave music and the music it plays during the scene at the end of the Gaea’s Cliff (You Can Hear the Cry of the Planet).
Well, you can get it off of Godo if you haven’t fought him already. The only other way I could think of is to find Stilva in the Gold Saucer arena (I’m not sure if it works though.) The Materia Keeper has it too, but you missed him. 8(
EDIT: You’ll have to go a little farther into the Dragon Skeleton area to get certain ones. Pollensalta is more common near the beginning of it (Manipulate her) and when you actually reach the fossils, Malboros and Dragon Zombies appear. You need a lot of HP to survive Pandora’s Box, so Shell yourself before you try and learn it.
Dalton, how in the world do you know everything about every game ever? It’s almost mind-boggling.
Because all I know is videogaming. Seriously. 8P
At least you know something. 
You must be going for a perfect game, correct?
Often people don’t really bother with E Skill at all. It’s not really a neccessary Materia.
But it’s fun!
See, now I disagree. Oftentimes, with such spells as White Wind, Big Guard, and the Four Elemental Spells (Trine, beta, Aqualung, Magic Breath), I rarely need any other materia!
This couldn’t be more true! Not only is Enemy Skill Materia stronger than the Level 1 and 2 spells that you’ll get through normal Materia (unless you level it up for a while), it’s easy to learn skills for, and has White Wind, Aqualung and Big Guard. Big Guard is infinitely useful (Shell, Protect, Haste), White Wind is damn good healing if one character is on high HP, and Aqualung can get you through pretty much anything the first disk throws at you. Also, there are no stat handicaps through Enemy Skill materia, and it doesn’t have to level up to get powerful!
I only found one problem with the Big Guard skill; Haste makes M.Barrier and Barrier wear off faster than normal. (I wonder if Slow makes it stay on longer?) Not that it still wasn’t very useful, I used it on almost every boss anyway.
One thing I like about E.Skill is it has some skills that you’d normally need two materia slots for each one of. Trine is a powerful Thunder spell with an All; and the same goes for Beta and Aqualung of their respective elements. Magic Breath is great for this too, although being tri-elemental it might heal the enemy by accident. Big Guard is especially good in for this since it’s essentially 4 materias in one.
As for other spells, Matra Magic is a cheap (8 MP) shot against all enemies that does fair damage too (although it counts as physical and might miss sometimes.) and it’s one of the fastest ways to level up early on. Death Force is cool cause it can stop Condemned (well, it prevents you from dying at 0). Then there’s the evil Bad Breath spell, which is fun to use on enemies. My personal favourite, though, is Shadow Flare, simply because it looks so awesome.
rants somewhat off topic about how cool E.Skill is
And Aqualung and those hit all enemy E.Skills are very good for getting your Limit Breaks up. Remember, Limit Breaks go up a level for every 80 or so enemies you kill (it’s 80 to get to Level 2, 160 to get to Level 3). Having Meteorain (or in some cases, Omnislash) on Disc 1 is pretty cool!
Remind me to someday tell you people about the time my sister Julia played FFVII, and decided to level up enough to beat the Midgar Zolom instead of trying to catch a chocobo to ride across the swamp. It actually made snese. She has the worst luck when it comes to finding monsters, and every chocobo she did find ran away before she could kill all the other monsters. It was really amusing to watch her kill Bottomswell in Junon Harbor in three blasts of Beta.
Uh, I got Beta from that worm as well, without insane leveling or that elemental absorb materia (I think). Was pretty fun. I somehow survived a blast of Beta, then managed to dish out my own Beta and killed it.