Zodiac
Aries: Basically, the creating of explosions. In the beginning, they will be more like fire cracker explosions, maybe cherry bomb like explosions, but never ever will there be atomic bomb like explosions. This power must be constantly monitored by the person controlling the character, as it can easily become god modding. In the beginning, more likely than not, your character will not be able to control where or when the explosions happen, so there are going to be a lot of little mishaps until they bring it under control.
Taurus: Control over the rock and natural metals of the earth. In the beginning, small pebbles, clumps of dirt, rocks perhaps the size of your hand, but nothing larger than that. As time progresses on, larger chunks of earth can be pulled from the ground, and even cracks formed in the ground. Canyon sized cracks are not aloud. It should be easy to tell when too much is too much. For developed powers, think about the earth benders from Avatar: The Last Air-bender. That's a nice example of what we're looking for.
Gemini: The controlling and creating of illusions. At first, only the slight warping of atmosphere, to create images that aren't there. They can't be large, or maintained for long periods of time in the beginning. Doppelgangers may be a possibility in the beginning, but control over the illusions may be a bit lacking. The character, at first, may have a hard time distinguishing between the accidental illusions they create and what is real. As the powers grow, later on in the collaborative, the illusions can be maintained longer, and will be able to inflict pain as well as confuse. They will also be able to grow in size.
Cancer: Control over water. Okay, in the beginning, your character can only use the water from puddles, lakes, oceans, rivers, etc. The ability to pull moisture from the air will be lacking until later on in the collaborative. The control over the water will only be slight, perhaps making it rise into the air to splash someone in the face, maybe knock them back, but nothing more. Later on, the water will be able to be better controlled, tidal waves, large amounts of water at the same time, whips, etc. Be creative, but keep it in check. A tsunami isn't something that your character should be able to do, that's a little much. Think the water benders from Avatar: The Last Air Bender.
Leo: Control over fire. For you pyro's out there, your character is only able to manipulate flame in the beginning of the collaborative. And at the very start, only small flames. If there is a forest fire, your character cannot run in and have all the flames extinguish themselves. No. As with the rest, the powers in the beginning will more likely than not, spawn randomly, so, candle flames may jump... those kinds of things. As the collaborative progresses, the ability to make flame by inducing a small amount of friction (snapping fingers, rubbing hands together, etc.) will become theirs. But the flames will never get so big as to cause huge problems. Fire-walls are an okay, but they will take much energy to control. Consider your characters position and ability when using the powers given to them.
Virgo: Control over things like plants. In the beginning, the character will simply have the ability to manipulate the growth of the plants, as well as their movement. But only small ones toward the start. You aren't going to be able to make a tree tear its roots from the ground and walk around. In the beginning, vines, flowers, thorny-vines, only those things around you, can be under your control, but for the most part, you can have them do what ever you think is alright to a certain point. If you have gone too far, I will alert you. Later on, the character will actually be able to summon the plants from the ground, for example, if you are in a desert, your character will be able to summon thorny vines from under the earth even though there had been none before. It is hard to god mod with this, so I trust the person who is controlling the character, to know what's right and what's not.
Libra: Light based powers such as holy and healing. This is also easy to god mod with. Alright, in the beginning, you aren't going to be able to do much, maybe blind people with a small flash of light, and heal little cuts, but that's all. So the character with light, in the beginning, is going to rely more on weapons, or is always going to hang toward the back. Once the powers begin to grow, the light attacks will actually be able to cause harm, burning skin (not like fire, think sun burn), and it can be used to dispel shadows that might appear during fights. The healing must be kept under constant watch. It will be no fun if your character gets hurt to the point where death is almost inevitable, heals themselves, then is as good as new. Healing, no matter how far the character progresses, will never be able to reattach or grow back a severed arm, bring back life to someone dead, or completely patch up a deep wound. It can completely heal small cuts, and partially heal those that are deeper, and heal only to the point that death will be narrowly avoided, to those that are really deep. The person who is healed when a near death wound is inflicted, will not be up and on their feet hours later. Please, watch this healing, the collaborative will be no fun if it goes too far.
Scorpio: Control over electricity. This can also be god modded with, so it also needs to be carefully monitored by the person controlling the character. In the beginning, the electricity they will use needs to be obtained from another source. An outlet, a light, static, something that can spark it. Static shocks are the only thing that will be able to be performed in the beginning, but as the character grows through the collaborative, they will be able to gather the electrical energy from the air, or use the electrical energy that is possessed through the natural human body. Things such as small lightening bolts will be able to be hurled, but the character will not be able to reduce anyone to a pile of ash. Sorry, I know it would be fun, but it's just not happening. The control of electricity is going to take a lot of energy from the character, so it won't be able to be used without care, and... toward the beginning, again that random outburst factor will more than likely exist.
Sagittarius: Use of sheer energy. Now this is obviously going to take a toll on the user, especially toward the beginning. It's hard to gather energy from the surroundings, unless you are rebounding energy obtained from something else back at them. Anyway, in the beginning, small pushes of energy will be all that is available, and maybe the occasional ability to speed up their run for a few seconds by transferring it to their feet. Later on in the collaborative, the energy blasts will knock people clear off their feet, sending them flying (no tearing apart of people, just knocking them back). They can transfer the energy to their feet allowing them to jump rather high (no flying), and can transfer the energy into their feet to allow fast sprints, they can't last long, maybe 10-20 seconds, as it would take a lot. After a while, they may be able to change that energy into a solid form, perhaps a weapon, or an attachment to the weapon they already possess, but it's going to take quite a bit of stamina to hold the weapons shape.
Capricorn: Dark based powers. Before I even start. Instant death is an absolute no no. You can never ever inflict instant death on any person. Now, in the beginning, this power will simply be the ability to manipulate small shadows. Maybe move the shadow of a beaker over there. Maybe, lift a shadow from the ground to trip a classmate, but nothing too much. Later on, shadows can be pulled from the ground, taking on their own form as a sort of 'servant' these however will be weak and dispel with a hit or two. Even later on, the shadow creatures can become larger and more powerful. These shadows can slip into small places, and sneak up behind the enemy. Other than shadows, much like a Libra, only opposite, they can push out dark energy. This dark energy gives a sense of foreboding to the person aimed at and, if the person allows it to stick to them, it can very slowly drain away the persons very life force. These take a lot of energy out of the character however, (in order to keep from god modding) so it should be used sparingly.
Aquarius: Control over wind. Never ever will they be able to create tornadoes, hurricanes, tsunami's anything like that. In the beginning they will simply be able to move things across the room with the wind already there, and maybe send a sort of blast toward those they grow angry with. Of course, doing such an extreme measure that early will have a toll. Later on, they'll be able to slow people by thickening the air, they may be able to put up a solid enough front of wind, to slow the strike of a weapon, and they will definitely be able to knock someone back a bit. However, the more powerful the measure, the more difficult to perform. They will never be able to create wind, only strengthen and intensify the wind already there.
Pisces: Control over ice. This is difficult to explain, and difficult to put specific limits on. In the beginning, they will simply be able to freeze water, so Cancer and Pisces might just be good buddies toward the beginning. As time progresses onward, and their abilities grow, the character will be able to freeze the air around them, to form balls of ice to use (or the slinging of razor sharp shards of ice). They will also have the ability, to freeze the air and make a thin shield that will slow weapons, or prevent injury from a fist. The shield however, will shatter easily, and will not be the easiest thing to form. The person controlling the character should know when practical crosses over to god modding.