If Zelda has taught me anything, the red ones heal, the green ones give you magic power, and the blue ones do both.
Also, here's a list of random tables for spicing up your potion drops.
This is one for those of you who like random tables and have always wanted potions to have more character.
Color (1d12)
1 Red
2 Yellow
3 Blue
4 Orange
5 Green
6 Violet
7 Black
8 White
9 Gray
10 Gold
11 Silver
12 Colorless
Taste (1d12)
1-2 Sweet
3-4 Salty
5-6 Bitter
7-8 Sour
9-10 Savory
11-12 Tasteless
Fragrance (1d6)
1 Floral
2 Citrus
3 Leathery
4 Wood
5 Putrid
6 Odorless
Consistency (1d12)
1-3 Watery
4-6 Creamy
7-9 Syrupy
10-12 Chunky
Opacity (1d12)
1-4 Transparent
5-8 Opaque
9-12 Translucent
Unique Characteristics (1d12)
1 Glows (equivalent to one candle)
2 Churns and/or bubbles for no apparent reason
3 Contains small colored flecks (roll for color and ignore a result of colorless or the same color)
4 Changes color when exposed to a trigger (roll below). Roll for the secondary color, ignoring a result of the same color.
Triggers (1d4)
1 Moonlight
2 Sunlight
3 Heat (>100 degrees F)
4 Cold (<32 degrees F)
5 Feels cold to the touch, like an ice cube
6 Feels hot to the touch, like a bowl of hot soup
7-12 Nothing unique
Container Shape (2d6)
2 Flat-bottomed cylinder
3 Round-bottomed cylinder
4 Flat-bottomed short-stemmed sphere
5 Round-bottomed short-stemmed sphere
6 Flat-bottomed long-stemmed sphere
7 Round-bottomed long-stemmed sphere
8 Egg-shaped reservoir with a short stem
9 Teardrop shaped reservoir with a pointed bottom and a short stem
10 Oval shaped reservoir, flat in front and back, with a short stem
11 A miniature bottle
12 Heart-shaped reservoir, flat in front and back, with a short stem
All containers are sealed with a stopper. Usually the stopper is made of cork, rubber, or wax. However, some stoppers may have a cap that conceals most or all of the stopper material. These caps generally screw on or are held shut by a latch.
Container Materials (1d20)
1-7 Glass
8-14 Ceramic
15-16 Leather (like a miniature waterskin)
17-18 Wax
19-20 Metal
Container Characteristics (1d12)
1 Decoratively engraved, embossed, or frosted with an image or symbol.
2 Decorative stopper cap.
3 Decoratively engraved, embossed, or frosted with a name or wording. Roll for a type of script then choose a language that uses that script.
Script (1d6)
1 Common
2 Elvish
3 Dwarvish
4 Draconic
5 Infernal
6 Celestial
4 Bears a loop or clasp large enough for a yarn or fine necklace chain to be threaded through.
5 The container is wrapped in a decorative metal filigree.
6- 12 Nothing special.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.