Angels, good or bad.
Also, Rulers; royals; those in power
or having governing authority, whether heavenly or earthly.
Also, "Divinity; a celestial or invisible being
or agent supposed to have dominion over
some part of creation; as celestial
powers; the powers of darkness."

See more on 'Powers' in, 
Webster's 1828    
...Put them in mind to be subject to principalities
and powers, to obey magistrates,
to be ready to every good work,
To speak evil of no man, to be no brawlers,
but gentle, showing all meekness
unto all men.

Titus 3:1-2
...And to make all men see what is the fellowship
of the mystery, which from the beginning of the world hath been His in God, who created all things by Jesus Christ:  To the intent that now unto the principalities and powers in heavenly places might be known by the church the manifold wisdom of God, According to the eternal purpose which He purposed
in Christ Jesus our Lord...

Ephesians 3:9-10