Image Optimization
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.
Photo Anonymizer
Photo Anonymizer bulk removes EXIF metadata from images. (free, MacOS)
(Windows users can download the free alternative from ASCOMP)
Keyword Research
Ahrefs
Yes, they’ve gotten expensive, but they’re also great.
SEO Optimization
Clearscope
Page Optimizer Pro
Frase
SEO Tools
Detailed Chrome Extension
The free Detailed chrome extension by Glen Allsop (aka Viperchill) is a fantastic tool.