I regularly find myself using https://yqnn.github.io/svg-path-editor/ - I wish Inkscape were that intuitive when handling the innards of <path>s, letting you convert between absolute/relative values and so on
I'll add one of my favorite SVG tools... a tool to crop SVGs. Sometimes the SVG has a wide border around it or something funky that makes dealing with centering it difficult. This tool just crops it to the visible elements:
Surprised this is being discussed here. It's worth noting that SVGOMG runs SVGO 3.0.0 while the latest version is 3.2.0 (so run SVGO locally for the latest optimizations), but I understand that once https://github.com/svg/svgo/pull/1943 is merged Jake will release an updated version of SVGOMG.
I've had this one in my bookmaeks as well for more than 5 years :)
Worth noting it deems itself "SVGOs missing GUI" (and does a splendid job at that). If one needs to batch process files or sth like that, svgo's CLI is still there.