Open SVG scenes you can recolour in the browser. Free for personal and commercial work, with no attribution, under the project's own licence. Redistributing the set or using it to train models is not allowed.
A mixer for illustration libraries by independent artists. The Blush licence allows commercial use in an end product, but not resale of the illustrations themselves or merchandising them as-is.
Illustration and icon packs. The DrawKit licence grants royalty-free use in your own commercial and non-commercial work, subject to the full terms on the site.