Here is the full list of all 20 Legendary Mahjong achievements.
Match 10000 tiles.
Complete all levels in all the temples.
Undo 100 moves.
Restore all the temples.
Restore the Temple of Wisdom.
Get the highest rank.
Restore the Temple of Air.
Restore the Temple of Time.
Use 10 Whirlwind Tiles.
Restore the Temple of Water.
Match 10 Ice Tiles.
Unlock the Celestial Gate.
Restart 5 times.
Restore the Temple of Earth.
Open 10 Box Tiles.
Restore the Temple of Fire.
Use 10 Magnet Tiles.
Match 10 Lock Tiles.
Get a new rank.
Match the first 2 tiles.