The lesson
Open a cold email by telling the recipient they're already being featured, then ask for two small things that improve their own listing.
The subject is "Featuring {{blog}} as a top sales blog". The body says Mark is putting together a roundup for the PandaDoc blog and will include {{blog}}, then asks for a 2-3 sentence intro in the blogger's words and a link to their best piece, naming {{article}} as a suggestion. Red numerals mark the three parts.
This only works if the roundup is real and the recipient benefits. Don't fake a feature to get a reply; keep the two-ask structure and the personalized article line.