Please add an icon for zstd compression format.
As well as an icon for zstd (application/zstd), there should also be an icon for application/x-zstd-compressed-tar (.tar.zst) similar to other compressed tar icons.
Perhaps the colour could match the zstd icon found at https://raw.githubusercontent.com/facebook/zstd/dev/doc/images/zstd_logo86.png