All of the terminal effects I display over at: https://chrisbuilds.github.io/terminaltexteffects/showroom/ were recorded using asciinema and converted to gif use AGG. https://github.com/asciinema/agg

The workflow only takes a few seconds. The .cast file is output to a folder, AGG reads the .cast and creates a gif. AGG has arguments to automatically set the row/column widths and strip inactive time.

I could not find any other solution that produced high quality gifs. Asciinema is awesome.