Pro tip for people with SVGs that have an image inside. You can pull that base64 image out of the svg, convert to image, compress it (tinypng, pngcrush etc) then convert back to base64 and out back in the SVG. We automated this with a slackbot but it’s often overlooked with all SVG optimization scripts.
Somewhat related: a while ago realized that the SVGs that draw.io generates (exports) have an interesting property. If you include an SVG inside such a drawing and you export it to SVG, that SVG is actually embedded as base64. This is unfortunately not supported by some programs (e.g., Microsoft Office). A quick fix is to actually expand the SVG into the big SVG. I wrote a quick tool for this that does this for you (I should consider open sourcing this maybe).
Anyway, I bet doing this and then minimizing the SVG could result in more savings?