Rayman 3 HD

The only Guide I was able to find on the internet that had ALL the Collectibles was this one:
Click HERE

An Act means the chapter you are in until you get the onscreen prompt of the number of stars and percentage. So the first level is Act 1, if you get the stars and percentage then the next level is Act 2 and so on.

The Fairy Council

Act 4:
Tribelle 1: Right before the first appearance of climbable vines.
Tribelle 2: In the room, where an enemy get's crushed by a big rock (that was a priceless moment), you will come across a big rock, where you can get on top of it by jumping in a tight space between two walls. Instead of doing that, go around the rock.

Clearleaf Forest

Act 2:
Tribelle 3: When you get to the big canyon, go down the first ladder you see. Then turn around so you face the direction, you've just come from. The Tribelle is right in front of the waterfall. Cage 4: This one is pretty obvious, and is unmissable, but you have to get to higher grounds again.
Tribelle 4: Keeping on the left side of the canyon, you will find a small passage through the wall. The Tribelle is at the end of the passage.

Act 3:
Tribelle 5: After the relatively long introduction to the orange power-up. You will be getting to some fort walls. If you face the direction you came from, you will see some boxes leading up to a small passage, the Tribelle is in there.
Tribelle 6: In the area where you defeat the grenade throwing enemy, there is a cave on the ground level. Look up, you'll see a walkway there, it is located up there.

The Bog of Murk
- None

The Land of the Livid Dead

Act 2:
Tribelle 7: There is a room filled with yellow crystals and balloons. The Tribelle is right below the entrance.

The Desert of the Knaaren
- None

The Longest Shortcut

Act 1:
Tribelle 8: After collecting ALL of the crowns and opened the door, you can see this Tribelle at the opposite side of the room.

Act 2:
Tribelle 9: After getting all the crowns and pushing the button, it's very obviously in the middle of the room.

Act 3:
Tribelle 10: At the beach area, behind some barrels. It's kinda out in the open.

The Summit Beyond the Clouds
- None

Hoodlum Headquarters

Act 1:
Tribelle 11: At the room with all of the hanging crates, kill the enemy with the dollar sign over his head to get a green power-up. Use it on screw-shaped mushroom at the right side of the room. The Tribelle is on the ledge you reach by using the mushroom.

Act 2:
Tribelle 12: After you defeat the enemies and you enter the next room, it is in the opposite corner.

Act 3:
Tribelle 13: You will eventually come to a part with a rotating machine with platforms attached. Jump down instead to find this Tribelle.