Links from associations and professional chambers are among the most accessible yet also most valuable sources for companies. Most unions, guilds, clusters, and chambers maintain a public list of members with profiles that include a link to the website. This is a topically related and trustworthy source that also confirms the company's professional affiliation, which matters not only for search engines but also for language models when recommending suppliers. Companies often pay for membership yet leave the profile empty or with outdated information. A practical step is to go through all the organisations in which the company or its people are involved, fill in a complete profile with a description of the specialisation, and verify that the link works. It is also worth getting involved in the association's expert output, where further mentions arise.
See also: Directories and consistent company data, Supplier recommendation in AI, Backlink profile.