Vector icons

Various libraries of vector icons are available online, either as SVG or as fonts. Here are some:

• The Noun Project
• Icons8
• SVG Repo
• Iconfinder

More complete and widely support but bloatier: font icons such as fontawesome.

Or: construct a font of just the icons you need. An easy tool for that is Glyphter or Fontello.

One can go both directions between fonts and SVGs via the tool fontforge.

• Export a glyph to SVG with fontforge command line
• Export a font’s individual glyphs into svg files in batch?
• Import a sequence of .svg files into FontForge as glyphs and output a font file