Power of Authority, Success, Karma, Material gains, Regeneration and Wealth.

This is due to the fact that Eight represents continuation, repetition and cycles.

This is seen in areas where success is obtained due to determination and repetition.

Also, matters of business and wealth largely depend on cycles to fulfill their manifestation.

It's snowball analogy: As it continues to roll, in gets bigger and bigger with each turn.

Eight represents that kind of momentum.

A mystic number associated with infinity, transient material plane, balance, equilibrium between opposing forces.

Planet - Pluto