There is already an amplify "effect" which applies equally to both channels of a stereo track. Also if you want to amplify L and R by different amounts you can split the stereo track into two mono tracks, and the controls at the left hand end of the tracks let you vary the level and L-R pan of each component - perfect for stereo recordings which are a bit unbalanced or where your L and R channels are really two instruments/voices and you need to blend them in to a narrower stereo image.

If I want to raise the level of a whole track without the odd peak getting distorted by overloading, I often use the "Fast lookahead limiter" plugin instead of "amplification". That works by applying gain (my main purpose) and then limiting peaks to a level you can set. -0.5dB or -1dB peaks are good if you want loud without anything overshooting.

Thanks for the link to that list of plugins, I noticed there's a peak finder there - I wish I'd known that a little while ago. It's going to be useful...