Squiggle Background Editor
The following tool allows you to generate Squiggle images at different resolutions and with different color backgrounds. You can also select transparent to remove the background altogether. The files generated are PNGs.
Please be aware that different software treats transparent images differently and it can depend on your platform. For example, Telegram on iOS will render a transparent squiggle as a sticker, preserving transparency, while Telegram on desktop will not.
Background: