I've done a moderate amount of taming. Leather and organics are the most sought after rewards. Organics are the best cash wise, and leather is just too hard to get in mass quantity (kind of wish tailoring rewards supplied more). Pet powerscrolls are alright, but take forever to find a buyer. Regular powerscrolls are nice, but I've only got one 120 in all my turn-ins. I just delete bio books, and cry at the 1k check I'm left with.
best leather I get is by carefully taming the mule of a master of arts champ, if tamed and not killed as most are they hold most all variety of leathers, if killed though, they hold nothing
You can get gargoyle knives easily by doing the fire champ solo and not proceeding past the stage with gargoyles that drop them. Once you have lots of gargoyle knives, turning that it to most leathers is not hard. Particularly in Fel where you get double leather.
Yes the fire champ. Poor druiders miss out on that trick
I don't think you get double leather (at least colored leather) by using a gargoyle knife in fel. I usually only use it on ancient wyrms, as they give the most leather, but then it's still only 40 hides of polar leather or higher. If you get a good elemental from the gargoyle knife you can use a master knife and get 60 (instead of 50) hides of that color leather.