Convert PNG to WEBP with Cloudconvert (free)
(Quite common for a 200 KB PNG image to turn into a 45 KB WEBP image without any loss of quality)
Remove EXIF metadata from images (free) with IMAGESMALLER.
Yes, they’ve gotten expensive, but they’re also great.
Page Optimizer Pro
Detailed Chrome Extension
The free Detailed chrome extension by Glen Allsop (aka Viperchill) is a fantastic tool.