Horizons already has consumables, such as potions (which impact the player directly), food (ditto) and fireworks (they look pretty). Here are some additional ideas for consumables that could provide an additional money sink in the HZ economy. They might also provide a laugh (see Aggro Punks).
Consumable thrown weapons. All races can use them. For the bipeds, these could be made by alchemists and tinkerers. They would include primitive grenades and firebombs, as well as poison gas bottles. Different varieties of these items could include effects such as DoT, AoE, or a hybrid of the two. There already exists an animation of a snowball being thrown, so it would not be overly difficult to change the color of the ball to indicate which type is being thrown.
Dragons would be able to construct similar items, except the consumable weapons they create reflect the two factions, Lunus and Helian. Lunus-type bombs fire off an electrical discharge when they explode. Helian-type bombs explode in a cloud of freezing gas. Again, there could be different varieties of dragon-made thrown weapons.
Consumable Combat Pets. I call them "Aggro Punks." Tinkerers and Dragon Crafters could make them. Good for a certain number of usages, the job of an Aggro Punk is (you guessed it) to hold aggro on a mob. They have a very high evasion, but can be easily destroyed if the mob gets in a hit. And, while very annoying to the mob, there is no guarantee that the Aggro Punk will work as advertised. They have a high %-chance of pulling aggro, but there is still a chance they will not. If they are destroyed, or they do not pull aggro, the mob will aggro the user. Similarly,only one Aggro Punk may be used bythe player (can'tsend out five of the little guys at once).
Aggro Punks made by bipeds could take such forms as: littlewind-up pygmybots; attack chickens; killer monkeys; "creeping toe-crunchers"; miniaturized "dire-cows"; mechanized spiders; spectral wolves anddoppelgangers.
Aggro Punks made by Dragon Crafters could take such forms as: miniaturized crystalline golems; magically animated stone garden gnomes (think Travelocity's Roaming Gnome); crystal/stone wolves and spiders; flocks of elemental (ice or lightning) ravens; and (my favorite) flaming sheep.
Just reading the types of Aggro Punk I've come up with, you can imagine what they would sound like when you unleash one against a mob.
Especially the attack monkey.
that's all...
(Yes, I know there's tons of other things that need to be done before a fluff idea like this should be considered. [;)])