Requires Unity 3.5.7 or higher.
This package features the Shuriken particle system with custom models and scripts. The package currently includes 65+ effects.
WEBPLAYER DEMO HERE
The effects are all prefabs, you can just instantiate them, they play the effect, then destroy themselves. Suitable for mobile phones and tablets too. If you have any questions, feel free to ask in the forums!
FORUM LINK Also there is a DEMO PACKAGE with 3 free effects so you can try before buying.
Please note that due to the way Shuriken is done, scaling the effects is not easy (not impossible, just tedious). The cubes in the demo are 1*1*1m, so the effects are "realistic" in size. There is a great effect scaler (link) that might help a lot though.