I use Pfsense and just today I switched from using duckdns to Gandi for my DDNS.
If you have a domain from Gandi you simply enter your chosen subdomain, domain, api key and TTL into the DDNS set up page within Pfsense and hit save.
Works well and is easier than I initially thought to set up.
There are many, many more options for DDNS provider within Pfsense. Eg namecheap, cloudflare, dnsimple, freedns, no-IP, Linode and many others
Check out my blog entry https://blog.x220.co.uk/pfsense-dynamic-dns-and-gandi/ @aral