Save Lucca's mother:
After saving Fiona's forest and going back in time to see Lucca's Mother. Head to the machine and enter "L1 O R1 O" which is the password to save Lara.

Developers' Room in FFIV:
There is a hidden Developers' Room, and it's in the hardtype version of FFIV (the one included with Chronicles), so here's how you get to it!

Go to the Dwarven Castle in the underworld. Get to the room where you can buy weapons and armor; there is a path in between both those counters. Walk up into the Rally-ho Pub. There, walk directly to the right (around the table of course) and you'll see an odd blackish section of floor. Walk right through the wall at that point and continue right and down the steps into the hidden Developers' Room!

There is also a hidden porn magazine in this room as well. Get into the Nap Room (from the entrance to the room, go up and right, then down into the Nap Room). Check out the left side of the bookcase nearby to find Smut, which is the magazine. Select it on the Item menu and the screen will turn purplish as Cecil looks at it... Then after it's over, the screen's back to normal and the Smut is gone.

Duplicate Weapons in FFIV:
First, get into a battle. Have the person who has the weapon to be duplicated select the ITEM command. Select a blank space in the item list, then scroll up and select the weapon to be duplicated. Exit the ITEM list and run away. Go to the menu screen and equip the item that you chose to be duplicated. It should say that you have two of that weapon. Unequip it and equip once more. You should have an extra weapon in the ITEM list!

(Final Fantasy 4) Skip Sealed Cave:
After you fight Golbez and get Rydia back in the Dwarven Castle, immediatly cast ''Warp'' when you get back to the kings chamber. You can pick up the crystal and therefore totally bypass the Sealed Cave (and Evil Wall). When you go into the sealed cave, it'll show the event that happens when you try to leave.

Chrono Trigger Infinite Shelters:
When you exit Guardia Forest in the beginning of the game there is a bush near the exit that will move, when you try to communicate with it a strange creature should run out dropping a free shelter, after this leave the forest twords the castle but don't progress further, instead go back into the forest to where the bush was, you will be able to interact with it again thusly giving you another free shelter. There are a few enemies about but by going around tho where th enemies come out you should be able to avoid them. By using this cheat you can use the shelters to recover many times or sell them for 75 gold each.