Air Anchor:
To get Edgar's Air Anchor skill, go to the Fanatic Tower, also known as the Magic Tower, and go to the 2nd floor (1st door you find). Go to the space directly right of the chest, look up, and press A. A new room should appear on the 1st floor. Go into the room and open the chest, which has the Air Anchor in it.

Imp Soup?:
If you want to become a 'true imp', such as the one that gives a few brief scenario instructions throughout the game, "Kappa", you must equip these four peices of equipment: Imp Halberd, Tortoise Shield, Titanium Helm, Imp Armor. Cast the 'Imp' spell on yourself. When in the imp status, and having all four peices of imp equipment on, you will be just as strong, fast, etc, as an imp, all char status is wiped clean and your character's abilities are that which the game has pre-set under the imp's skills/spells and attributes.

-To get a completely different ending(s), you only use Setzer, Celes, and Locke to defeat Kefka. This is "hard", but the ending is completely different!
-If Cid dies then Celes tries to kill herself by jumping off of a cliff. To prevent this, only catch fast fish for cid to eat and he'll live.
-If you get all of Shadow's Dreams, Baram won't die at the end, and he won't make interceptor to go away.

Shadow's Dreams:
After going on the Lete River, there are 3 scenarios. If you do the scenario with Sabin and Shadow last, Shadow will stay with your party somewhat longer.

3rd Momento Ring:
There is another Momento Ring in Strago's House (located on the very bottom right island on the map). Go to the 2nd floor and go to the left middle corner of the room. You need to go in between the chair and the wall, looking down, farthest down possible. Press A, and receive it. Only Shadow, Relm, and Strago can wear the Momento rings. This allows all three to have one equipped at the same time, if needed.

Moogle Charm:
To get Mog's Moogle Charm, go to the exact spot (or space) in the caves that you found Mog, and press A...
If you found Mog in the far north part of the town, and not in the caves, then go to the room with all of the moogles. There is a space, at the top of the cave that you must be on. Assuming that you are entering the room from the south door, go strait up until you hit the wall and can't go any further. Look up, Press A, and receive it.

Cursed stuff:
-To get the Paladin Sheild, you have to go to Narshe, in the World of Ruin. One of the houses in the upper left section of town has a treasure chest with the Cursed Shield in it. You must have Locke in your party to unlock the doors of the shops in Narshe. You must have it equipped for 255 fights. If you un-equip it, save the game, or use a tent or sleeping bag, it won't change a thing. Rather, so long as it has been equipped for 255 battles that the wearer has lived through, a message to the effect of "The curse has worn off" will appear at the top of the screen at the end of the battle, and you will find a "Paladin Shield" equipped instead of a "Cursed Shield". If you use the relic "Ribbon", it will counter-effect everything but the "Death Sentence" for the the 255 fights. You also may fight the 255 times anywhere at anytime with anyone, except on the Veldt. I suggest going to Solitary Island with the Black Belt relic equipped on your character(s) and a Tintinabar equipped on your character(s). Also note that the Paladin Shield teaches the wearer Ultima at the rate of x1. This would enable you to get both the Ragnarok Sword (to trade for the "Illumina" sword, the best sword, at the colloseum) and learn Ultima.

-One of the ways to get the Cursed Ring is to go into Kefka's tower and into the Gold. Drgn's room. First you must beat the Gold. Drgn and then get into a fight with a monster in that same room. Use the Ragnarock Esper on the enemy, and at the top of the screen, it should say something like: "chosen to get Cursed Ring". When the battle is over, you will receive the Cursed Ring. On some SNES versions and on the Final Fantasy Anthology versions, this is merely a text glitch. You will still see the "chosen to get Cursed Ring", but you will never find it in your inventory.
Most sources I have read, all claim that the cursed ring can not be uncursed. Some suggest it can be uncursed after 255 battles, just as the cursed shield can. I personally trust the sources that claim it cannot be uncursed.

Level 99:
Every person in this world by now has probably heard of this, even if they've never played FF3. Anyhow, for you new-comers: On the beginning of the Lete River Before you get on the raft go to the menu and then to configuration, set the controller to memory, this way what you attack with, will automatically be set to that every time you go back to that character. You make LOADS of experience off of this. Also set Banon's attack to heal, it doesnt really matter what you set everyone else's attack to, as long as it is tools, or fight. If you have anyone cast magic (aside from Banon's "Heal" skill), you are a complete idiot. On the Lete river, first go right, then go up. Set the turbo controller (or leg of a chair..) on the "Confirm" button. Make sure that it is on menu-screen: configuration: memory! Now, sit back and watch your levels jump up with no effort what so ever.

How to get Leo:
-You can sketch a vanished Gabledegak (Zozo) and Edgar should turn into him...
-Neither trick works on the Final Fantasy Anthology version of FF3. (I've tried..)

I had something of an interview with the guy who created this 'rumor' (below). This was in mid 1998 over ICQ. Still, he claimed it to be true. He was rather convincing, so, I figured I'd go ahead and post it as though it were true - eventhough I'm confident it is merely a rumor..

-"All right. I have Leo. No Game Genie, no glitch, I truly have him! I think this has to do with me owning an early release version of FF3, but here it is." (-referring to the very first SNES release) "Fight 4000 battles in the dinosaur forest after beating the Gold Dragon in Kefka's tower. A special dragon (like the ones on the floating continent, only gold) appears. He was incredibly strong, but I won. I won an item called "Resurect" from him. I went to Leo's grave, and used the item on the grave, and he appears in front of the grave. He thanks you, and goes and talks to Terra. They finish their little conversation that they started on the ship to Thamasa. In the end, he saves Shadow, and this also introduces a whole new ending. All the characters settle down and start a life. Locke & Celes marry, and there's a lot of other things. Very few have believed me yet, but I keep trying to tell people. You must fight 4000 battles (Maybe I have too much free time!?)."