Justin Sandercoe gave a cue about power chords and progressions...

Moral issue: I like the tutorial bit, bit not the bit about "sounding wicked" or doing the "devils sign" a k a corni. While you are at youtube, have a go at this.

Now, he is giving all power chords, all X⁵ as base note + 5 + 8, AND he is putting all base notes on the sixth string. Maybe that is the siplest way to find them. I have some other ideas, though. To start with, the exactly same chords can also be played without putting all base notes on sixth string, like this:

First progression, I⁵-IV⁵- low III⁵- lowVI⁵ or F⁵, B flat⁵, A flat⁵, D flat⁵:

133xxx
x133xx
466xxx
x466xx
or
133xxx
x133xx
4x11xx
x4x12x

In the second variant, you will get a muted string between two sounding ones. Maybe that is wrong or impossible to do when strumming, but not when picking each chord singly.

Second progression, I⁵- low III⁵- low VII⁵-IV⁵ or A⁵ C⁵ G⁵ D⁵:

x022xx
x355xx
355xxx
xx023x
or
x022xx
x3x01x
3x00xx
xx023x

Same remark as above on second variety.

Third progression, I⁵-V⁵-IV⁵-V⁵ or G⁵ D⁵ C⁵ D⁵:

355xxx
xx023x
x355xx
xx023x
or
3x00xx
xx023x
x3x01x
xx023x

But then again, there is another way to spell a power chord out, I think: base note - 8 - 12 (i.e. 5 over 8): that way the classic ban on parallel fifths and on parallel octaves can be observed. On the other hand, that does mean leaving mute strings between played ones, and may therefore involve the obligation to pick each string by its own finger rather than strum the whole chord.

Here is first progression thus modified:

1x3x1x
x133xx
4xx14x
x4x12x

Here is second progression thus modified:

x0x2x0
x3x01x
3xx03x
xx023x

The third I have both modified and transposed (G⁵-D⁵-C⁵-D⁵ - E⁵-B⁵-A⁵-B⁵ - F⁵-C⁵-Bflat⁵-C⁵):

3xx03x
xx023x
x3x1x3
xx023x

0x2x0x
x24x0x
x0x2x0
x24x0x

1x3x1x
x3x01x
x1x3x1
x3x01x

Now, a tip: two power chords should NOT be a half tone (i e a fret per base note) apart. It would include a tritone relation, and that is ugly.

Hans-Georg Lundahl
Paris XI, Faidherbe
23 sept 2009