Air Scroll: In the Air Temple (Chapter 6), go west and north after getting out of the temple. When you get there you will have to play ''The 4 Nations Force'' game with the spirit of Gyatso. It does not matter if you give up or lose. You will get an Airbending Scroll. Use it to get a tornado-like attack for Aang (you can move it).
Earth Scroll: In the Air Temple (Chapter 6), go to the south and find the Earthbender. Talk to him and win the challenge. Then, use the Scroll as done the last time. You will get a similar move to Haru's Boulder-Kickin', but it will be slower, bigger, and more powerful.
Water Scroll: In the 4-Paws Island (Chapter 5), go through the middle of the island and turn upside. You will fight a monster. When you defeat it, it will hide. Follow it and search for the yellow chest. Enter two key items and use the Scroll. You will get a water bending power for Katara (revives your friends in battle).