I have mentioned a few times that magic items and spells make good artifacts in Gamma World and Mutant Future. Using some wands from from the AD&D First Edition Player's Handbook and Unearthed Arcana, here is an example, the thermal manipulator.

There are several different kinds of thermal manipulators- gauntlets, boxes, robotic accessories, vehicle accessories and others. Most have the same basic functions:

Wand of Fire- burning hands, pyrotechnics, fireball, wall of fire

Wand of Frost- ice storm, wall of ice, cone of cold

Wand of Illumination- dancing lights, light, sunburst

Wand of Defoliation- destroy chlorophyll, kill plants

Wand of Flame Extinguishing- put out normal fires, put out large fires, put out plasma fires

Wand of Steam and Vapor- create steam, create vapor

So there are 17 basic functions. The exact effects of those powers (i.e. range, duration, damage) should be determined by the GM when the PCs get their hands on one. Advanced functions can include spells like meteor swarm, freezing sphere and raise/lower water. The person who studies the manipulator has to discover each function seperatly. That means at least 17 times through the chart(s), each with the potential for disaster, if one wants to find out all the things the artifact can do. Most people stick to one or a few functions to prevent personal incineration.