I work at LottieFiles. This is a library of animated UI icons (MIT), plus a CLI so a coding agent can create a missing one and the same style.

They're standard dotLottie files (or animated SVG). Color, style and weight live in the file as slots, set at runtime.

No account for the existing icons. Creating a new one runs Lottie Creator MCP (headless) under the hood to do the animation. That needs a LottieFiles login, and the CLI is macOS and Linux only.

https://github.com/LottieFiles/generative-icons