Many object show community servers have resource channels. How to Use Them (Workflow):

The mouths transitioned to smoother, cleaner vector lines. The line thickness became standardized, and the shapes became more fluid to accommodate higher-quality rigging and smoother interpolation in Adobe Animate. How to Use BFDI Mouth Assets in Animation

If you want to avoid copyright issues entirely, many fans have created tracing recreations of the BFDI mouth style using Adobe Illustrator. Search for "Free BFDI Style Mouth Vectors."

If you are looking to create your own object show or meme animation, utilizing these assets is straightforward:

Up close, Four saw the truth. The mouth wasn’t a mouth. It was a piece of code. A string of coordinates, bezier curves, and a single parameter: [emotion: SAD] . And at the bottom of the asset file, in tiny, blinking text: