A GIPHY allowlist to pair with a pan-facebook blocklist such as Developer Dan's Facebook blocklist. This allowlist contains GIPHY domains, with the exception of known cookie/analytics GIPHY domains.
Facebook has been ordered to sell GIPHY, so it's possible that this allowlist will eventually become obsolete if/when the pan-Facebook blocklists no longer include GIPHY domains.
note to self: bulk add to pihole with pihole -w domain1 domain2 ...