Hey there, fellow Final Fantasy X explorer! When it comes to side quests, there are a few key ones you definitely don’t want to miss out on.

1. **Monster Arena**: Be sure to capture all the fiends in each area to unlock powerful monsters in the Monster Arena. It’s a great way to level up your characters and earn rare items.

2. **Dark Aeons and Penance**: After defeating Sin, challenge the Dark Aeons for some intense battles. Be prepared, they are tough! And if you’re feeling really ambitious, take on the superboss, Penance.

3. **Celestial Weapons**: Each character has a Celestial Weapon with unique abilities. To unlock their full potential, you’ll need to complete various tasks like dodging lightning bolts in the Thunder Plains or racing chocobos in the Calm Lands.

4. **Al Bhed Primers**: Collecting all the Al Bhed Primers scattered throughout Spira will not only help