Rocket Page Speed Optimizer

Kinda works, but its highly inflexible (breaks other apps with no way of whitelisting them), the implementation is very weird, it updates your theme daily (or more) to change an expiry date. If this date is reached it wont work anymore, as a way to break it when you uninstall it. Generally this works completely without a server, so a one-time payment would make more sense. Instead they have a monthly fee for doing basically nothing after installing, other than messing with your theme.

Customer service also never answered my question for a way to whitelist scripts.

Better use another app, that ain't it.