The subject did half the work, or they did not
Most of the tools in this track ask a large number of sites a repetitive question: do you know this handle? Linkook is here because that question is not always the best question. People publish links to their other accounts. A code-host README, a bio with three handles, a personal site with a row of icons, a link-in-bio page. Those links are statements the person made on purpose, in public. Following them is closer to reading than to trawling.
Linkook helps collect linked social accounts, and emails when those emails are actually published on the pages it can see. The Consensus snapshot counted a small username-site list next to Maigret's thousands. If you came here for coverage, you came to the wrong lesson. The value is the edge between two accounts, with a page you can cite. A tool that returns fifty unexplained URLs has not done Linkook's job. It has done a shy version of Sherlock's job.
It will not invent links that are not on the page. A quiet subject stays quiet, and that quiet is a result. A person who treats their handle as a brand will hand you a map, because the map is the brand. Both outcomes are allowed to be the end of the enquiry. "The tool found little" does not trigger a fallback to blasting four hundred sites unless your purpose sentence says that is the next step. Often it should not.
Parsers read HTML. They miss what a browser only builds after JavaScript runs. They also "find" links that are site chrome: the forum's own Twitter, the template's placeholder, the "share this" button. Your job is to keep those out of the graph. Linkook's job is to show you candidates. Candidates are not edges.
Brute-force username search is a trawl. Link following is reading the brochure they left at the door. If there is no brochure, do not forge one.