unDraw is Katerina Limpitsouni's open-source illustration project: a flat, minimal style applied consistently across what's grown into a fairly large library, with color recoloring built right into the browsing page.
The on-page recolor tool means you pick a hue and every illustration you grab already matches, instead of recoloring SVGs by hand afterward.
Probably the most-used flat illustration set for SaaS marketing sites at this point, precisely because the style is so neutral and the recoloring is so easy.
The core library is free; unDraw+ is a paid supporter tier that adds animated scene variants on top of the static ones.
Open-source illustrations you can recolour to match any idea.
