Let's Look at Unofficial Yaku (That we will never use)

There are literally dozens of variations of mahjong with hundreds of optional yaku that can be used, so today I want to introduce you all to some 'house rule' yaku that other people occasionally use. Note that these are NOT used in our McGill Students' Mahjong Club Hong Kong Old Style games (Though some of them are used in our Japanese Riichi style games).

Three Chained Pungs (+2 Fan)
Having three consecutive pungs in the same suit, such as pungs of 2-dots, 3-dots, and 4-dots.
Four Chained Pungs (Limit Hand)
Obviously having four consecutive pungs in the same suit.
Great Chariot (Limit Hand)
Sometimes this yaku is called 'Big Circles'. A concealed Seven Pairs hand, where the pairs are the 2 through 8 of dots. The McGill Students' Mahjong Club now treats this as a valid limit hand.
Lesser Chariot (+2 Fan)
A concealed Seven Pairs hand of dots, but the pairs are either 1 through 7 of dots, or 3 through 9 of dots.
Bamboo Forest/Numerous Neighbors (Limit Hand)
These hands are identical to Great Chariot, only in the bamboo/characters suits instead.
Red Peacock (Limit Hand)
The opposite of a Perfect Green hand, this hand is made up of only the red dragon and bamboo tiles that contain red in them (1, 5, 7, and 9). The 'peacock' in the yaku's name represents the 1-bamboo.
Perfect Black (Limit Hand)
A hand containing only the wind tiles and the dots tiles traditionally done in black ink (2, 4, and 8).
One Million Years (Limit Hand)
A Full Flush of characters where the total value of your tiles adds up to at least 100 (For example, if you had a gong of 9-characters, the value of that gong would be 9 x 4 = 32). This yaku gets its name from the fact that each character tile represents X0,000, so if X is at least 100, your hand would represent 1,000,000.
Thirteen Unconnected Tiles (Limit Hand)
Your opening hand contains at least 13 tiles that cannot form any melds with any other tiles in your hand (So they are not pairs or are too far away to combine into any chows). Must be declared on your first turn as a self-pick win before discarding, and cannot be earned if any open melds or concealed gongs are made before your first draw.
Plum Blossoms in the Moonlit Snowstorm (Limit Hand)
A hand containing a pung of 5-dots (representing plum blossoms), 1-dots (representing the moon), white dragon (representing the snow), and the seat wind or round wind (representing the storm). This gets points for being the most specific yaku I've ever heard of, but at least it's poetic!
Beauties of Nature (Limit Hand)
Yet another unnecessarily complicated hand! The Chinese characters for this hand are literally 'flower-bird-wind-moon', so this hand needs a pung of 5-dots, 1-bamboo, the seat or round wind, and the 1-dots.
The Tohoku Shinkansen (Limit Hand)
A concealed hand containing one of each bamboo tile and a pung/pair of the east wind and north wind. The Japanese town 'Tohoku' is literally written as the Chinese characters 'east-north'.
The Tohoku Express (Limit Hand)
An all pungs hand containing the east wind, north wind, 2-dots, 4-dots, and 6-dots (The dot tiles here allegedly represent motorcycles, cars, and large trucks respectively).
American Civil War (Limit Hand)
A concealed hand containing pungs of the south wind and north wind. The remaining eight tiles must be any tiles of the numbers 1, 8, 6, 1, 1, 8, 6, and 5, and do not need to match suits. The American Civil War between the north and south lasted from 1861 to 1865. The more you know.
Golden Gate Bridge (Limit Hand)
A hand whose four melds are all chows in the same suit, and the chows are 1-2-3, 3-4-5, 5-6-7, 7-8-9.
Five Families (+2 Fan)
An All Pungs hand containing dots, characters, bamboo, dragons, and wind tiles.
Seven Pairs with Honor (+1 Fan)
A Seven Pairs hand that either has three pairs of dragon tiles or four pairs of wind tiles.
Pure Run (+1 Fan)
A hand containing the chows 1-2-3, 4-5-6, and 7-8-9 in the same suit.
Broken Pure Run (+1 Fan)
A hand containing a chow of 1-2-3 in one suit, 4-5-6 in a second, and 7-8-9 in the third.
Reflective Tiles (+1 Fan)
A hand composed only of tiles that have vertical symmetry (2, 4, 5, 6, 8, 9 bamboo, 1, 2, 3, 4, 5, 8, 9 dots, and white dragon).
All Simples (+1 Fan)
A hand that does not use any terminal or honor tiles.
Double Chow (+1 Fan)
Using two identical chows in your hand (i.e., 2-3-4 bamboo and 2-3-4 bamboo).
Three Colors, One Chow (+1 Fan)
A hand that has the same chow in all three suits (i.e., 6-7-8 in dots, bamboo, and characters).
Three Colors, One Pung (+2 Fan)
A hand that has the same pung in all three suits (i.e, 1-1-1 in dots, bamboo, and characters).
Three Gongs (+2 Fan)
This should totally be a valid yaku in Hong Kong Old Style, I'm just saying.
Three Concealed Pungs (+2 Fan)
Just like the Four Concealed Pungs limit hand, you won't score this yaku if the third pung is made with your winning tile unless you self-pick it.
All With Orphans (+1 Fan)
Every meld in your hand (including the pair) contain a terminal or honor tile. That means that your hand is made of pungs of terminal/honor tiles, or chows of 1-2-3 or 7-8-9.
All With Terminals (+2 Fan)
Every meld in your hand (including the pair) contain a terminal tile. That means that your hand is made of pungs of terminal tiles, or chows of 1-2-3 or 7-8-9.
All Orphans (+2 Fan)
Every tile in your hand is a terminal or honor tile. That means that your hand is made of pungs and a pair of terminal or honor tiles.