Particle ProFX one is a unity package with high quality particle prefabs.

Video | Webdemo

This package includes:
- 58 Prefabs
- eight chain reaction prefabs
- Four custom flares
- High quality sprite sheet textures
- Library tool, for quickly previewing each prefab (you can add your own prefabs to the lib too!)

Scripts included:
- Scale script: easily scale particles
- Chain reaction script: create stunning chain reactions
- Physic force script: add physical force to your explosions
- Meteor script: create awesome meteor effects (also cool for railguns or other lightstreaks effects)

Note:
The preview in the library window is only available for Unity Pro users.
But it is still possible to click through each prefab in the library and preview them in the scene.