Candidates come from the places link builders already share opportunities: resource pages, roundups and community lists. They land in a review queue, not in the directory.
Each one is opened before it's listed, to confirm it loads, that you can really add a link to it, and that it isn't a parked domain or a link farm. A site that fails any of those stays out.
Listed sites get checked again every week. When one goes down, its listing shows it, so you find out before you spend an afternoon on it.
A few of the sites listed under each type, with their domain authority. Sign in to see the full listings, filter them and add them to a project.
The links that do the most for rankings, and the most work: you pitch, write and wait for an editor. Read a few recent posts first and check whether they carry a "sponsored" label.
Free blogs on hosted platforms. You control the page, so the link counts for as much as the page around it does. A thin post with one link in it counts for very little.
An account page with your site on it. Fast to set up and usually nofollow. Worth having for brand searches and a natural mix of links, not as a ranking plan.
Answer the question properly and the link in your post brings people who wanted it. Post a link with no answer and a moderator removes it, sometimes with the account.
Business and niche listings. A few relevant ones help people and search engines confirm who you are. Hundreds of general ones add nothing, so pick by niche, not by count.
Sites for saving and sharing links. Mostly nofollow, but a bookmark can help a brand-new page get found.
Sites that publish contributed articles. Quality changes a lot from one to the next, so look at what else they publish before you send yours.
Upload something people will use, like a checklist, a template or slides, with your link inside it.
Add the sites you want to a project and keep track of what you submitted where. Once a link is live, the Backlink Monitor checks it on a schedule and sends you a notification if it goes missing, so you hear it from SerpCrest and not from a ranking drop three months later.