Add support for PayPal’s PayFlow Link
...We would also like to see PayPal’s PayFlow Link supported as well and although that system requires using their Hosted Checkout Page, it would be nice to not have to spend the $25 on the PayFlow Pro...
PayPal has decided to discontinue further development of Payflow Link, it is stated as Legacy system in their docs and available only for existing users.
So we will unlikely support it, unless PayPal decides to revive the project.
PayPal documentation link: https://developer.paypal.com/docs/classic/products/payflow-gateway/