Scribes can craft random Darkmoon Cards of Destruction which make one of a Ace to Eight of Card of Waves / the Winds / Embers / Stone. They cost 10 inferno inks + 30 volatile life + 1 resilient parchment. On my server that costs 360 gold. Or, if the inferno inks are milled as part of milling blackfallow inks then the cost is down to the 30 volatile life + 1 resilient parchment which is 210 gold.
Put an entire eight cards of Ace through to Eight together creates a deck of Tsunami / Hurricane / Volcano / Earthquake which can be used by another player in the Darkmoon Faire to create a trinket of various abilities.
These cards and decks can only be created by Scribes. Either the cards or the deck can be sold on the Auction House. And they sell best at the time of the Darkmoon Faire.
My strategy here is to buy the volatile life from the Auction House in the periods between the Darkmoon Faires for under 7 gold each (during the Darkmoon Faire the volatile life cost rises significantly) and allow my stock of Inferno Inks to build up as i mill cataclysm herbs. The day before the Darkmoon Faire i will craft all the Cards i can and i aim to sell the cards for a minimum of 400 gold each during the Darkmon Faire.
i occasionally sell the Decks which i can put at least at a 30% mark up to the sum of the cards - but that is a risk. Furthermore, my cards can be sold to those buyers that are willing to take that risk to put the cards together to make a Deck to flip onwards.
Those that consistently go for less than 400 gold i send to my "discount alt" to sell at best price.
The rest go for in excess of 400 gold and a comfortable average of 1000 gold.
During the Darkmoon Faire i will regularly make sales of 30000 gold from these Cards. It is a high but lumpy income that occurs each month. Every Scribe should take part in this.
for this and other ideas on the glyph market please follow the link to the free Croda's Inscription Gold Guide