Improve plugin documentation

[NathanJAdams]

Is your feature request related to a problem? Please describe.
None of the plugins I've looked at have explanations of what they're for or what they do

Describe the solution you'd like
A README.md for each plugin describing what it does, potentially an example input/output

Describe alternatives you've considered
Testing them to see their effects
Reading through the source to see what they do

[Urigo]

would you mind helping us to improve the docs by sending some Pull Requests? thank you!

[NathanJAdams]

Maybe I should've been more clear, without any documentation I have no idea what the plugins do