Hi! I've built a tool for creating animated gifs and spritesheets:  https://unholybear.itch.io/pixelapp

The app also has an online version, linked on the page.

The app itself is built with Javascript, utilizing the browser's canvas2d API, using React.js framework and Electron for building the offline desktop version. I've created a set of appropriately pixely looking f and a font.

It was all around a challending and fun experience.