For our chain icons, we use Edge & Node's Token Icons library. The library is a collection of SVG icons for various blockchain tokens and chains. The library is available on GitHub, NPM and Figma.
We wrote a script to leverage the library's metadata (in the final data.json generation script), to make sure that the chain icons are up-to-date with the latest changes.
The copy_token_icons.ts script iterates through our supported chains and makes sure that every mainnet has its associated token-icons logos. The script will attempt to retrieve the branded and mono versions of the chains logo. It will then copy those over and with the mono version of the logo create the dark and light variants. For more information, please read chain_icons.md.
If it can't find them, you'll receive an error and may need to provide an ID match in the script's code.
See copy_token_icons.ts for more information.