Cooking? Maybe not the most exciting profession ever, nor the most exciting thing to datamine. However, I have a strange love for seeing what gross ingredients will be going into the food our characters will be eating in a coming expansion. The latest patch to the Warlords of Draenor alpha included a number of those items.
Rylak Eggs are used in many recipes and, for now, appear to be the base of most Warlords cooking. Fishing continues to be heavily involved based on items like Sea Scorpion Segment, Blackwater Whiptail Flesh, and so on. Each type of fish indicates that a special form of bait can be used to catch them -- or perhaps, must be used to catch them.
Certain complex foods even require you to combine basic foods to create them. For example, Calamari Crepes require both Rylak Crepes and Fiery Calamari. Interestingly, the crepes also require something called a Nagrand Arrowbloom, gathered with herbalism. It seems to me that if you're hoping to be a chef in Warlords, you'll need access to either fishing or herbalism, if not both. Remember: your garrison can give you limited access to certain professions even if you do not know them yourself.
The stats on some of these items seem incomplete, with some complex recipes restoring less health or mana than the base recipes from which they're made. That will surely change in the relative eternity we have before launch. If you want to look at all of the currently datamined recipes and reagents, check out Wowhead's extremely convenient list.