To find the best resources for where you might find great links or people that might want to link back to your content, search and review your competitors, and find out who’s out-ranking you. Look at the recent activity and start finding the content they link to and then start thinking about how you could make a pitch to this website or influencer in a way that would make them want to link to you. If you were trying to find people that do roundup posts, say for link-building, you would just type in Title, Column, Roundup+link building, and you would find a bunch of roundup-type of posts or a list of sites that run roundup posts.