General:
* Rain: Raindrop
* Water: Waterdrop
* Blood: Blooddrop
* Oil: Oil drop
* Ink: Ink drop
* Paint: Paint drop
* Honey: Honey drop
* Juice: Juice drop
More specific:
* Eye: Eyedrop
* Ear: Eardrop
* Nose: Nosedrop
* Teardrop: Tear drop
* Droplet: A smaller drop
* Drip: The act of dripping
* Drizzle: A very light rain
* Pitter-patter: The sound of drops hitting a surface
Figurative:
* Knowledge: Knowledge drip (meaning a slow but steady acquisition of knowledge)
* Fashion: Fashion drip (meaning stylish clothing)
The best prefix for you depends on the context and the meaning you want to convey.