random.lua

blacklist = {'master', 'amp attack'}

function isBlacklisted(name)
  blacklisted = false
  for i, item in pairs(blacklist) do
    if name:lower():find(item) ~= nil then
      blacklisted = true
    end
  end
  return blacklisted
end

retval, tracknum, fx, paramnum = reaper.GetLastTouchedFX()
if retval then
  track = reaper.GetTrack(0, tracknum-1)
  numparams = reaper.TrackFX_GetNumParams(track, fx)
  for param = 0, numparams-3 do
    r, name = reaper.TrackFX_GetParamName(track, fx, param, "")
    if r then
      if not isBlacklisted(name) then
        reaper.TrackFX_SetParam(track, fx, param, math.random())
      end
    else
      reaper.TrackFX_SetParam(track, fx, param, math.random())
    end
  end
else
  reaper.ShowMessageBox("Please touch any parameter of the target FX.", "Error", 0)
end