[2024-12-09: Honestly, today I'd probably recommend using https://scratchblocks.github.io/ now. If I recall correctly, SVG exports from it work properly in Scratch now, instead of being offset. It also lets you make anything and is fully Scratch-accurate.] Put Scratch blocks in costumes without needing to export from the scratchblocks site! The way I did this is basically I just created a big bunch of templates with the scratchblocks site, exported them as SVG and exported and arranged them in the paint editor. The text and icons were offset so I had to fix them. I also gradually made more templates if I forgot something. Also note that the block font is fragile so it may turn into sans serif at times.
No credit needed as it's just Scratch blocks. Sorry if some stuff is a bit offset. Keep in mind that I never compared these to the pixel with the real Scratch blocks so it was just moving it to what seems right..