Iconfinder Iconfinder provides high-quality icons for web design and desktop apps. Designers, this is the best place to download free icons, in various sizes and formats.

Flaticon Flaticon offers users free access to thousands of free vector icons. It also has a premium plan for more exclusive resources and premium features.

Icons8 Icons8 is a comprehensive library of free icons, photos, UX illustrations, and music for your videos. All assets are free to use under a Creative Commons license.

Based on your query, I would recommend Iconfinder. It is a dedicated platform for icons, offering a vast database of high-quality icons for various purposes. You can download these icons in different sizes and formats, which gives you the flexibility to use them as per your specific needs. The platform is designed to cater to designers, making it a suitable choice for educational purposes where design and visual aids play a crucial role.