UI Faces aggregates various free avatar placeholder sources that you can use in your design mockups by copy—paste, API, plugins for Sketch, Adobe XD and Figma.

Bootstrap Logos is a stock logo store for builders, makers, and people with big dreams but small budgets. When purchasing a logo you will receive PNG, AI, EPS, and PDF files. Update the colors in Illustrator, sketch, or any other vector design software. Logos are $10. These logos are non-exclusive (stock).