Ok so hear me out. I am in a newly touring band and want to ditch my amp, so that I have less to carry around and setup. I use a Boss ME-80 as my main and only provider for effects/tone. When I do run into an amp, that amp is set to a clean tone and a direct input into a Direct Box -> soundboard.

I have run the Boss ME-80 directly to the board before and it sounded really bad. Since the Boss already has a built in preamp, would I need a Power Amp pedal to act as my signal booster, aka my amp, or what do I need to clean up that signal so that I can just run directly from my Boss to the board?
It sounds bad how? My guess is that you are referring to having too much annoying hi-end that makes it sound tinny. If that is what you are talking about, it's because the ME-80 lacks a cabinet simulation. A speaker cabinet naturally acts as a sort of band pass filter, with the hi-cut being the most obvious. That's what I'm guessing without specific details anyway.
There's no such thing; there never was. Where I am going you cannot follow me now.