The SEO agency Aira conducts an annual State of Link Building survey. In the latest edition, 270 SEOs voted for the link-building techniques they currently use. The seven tactics discussed in the content are:
1. Creating content that generates links, also known as link bait. This involves creating valuable and interesting content that others want to link to.
2. Analyzing competitors’ links and replicating their successful strategies.
3. Guest posting on websites that already receive a lot of traffic on similar topics.
4. Using reactive PR, such as responding to journalist queries on platforms like HARO.
5. Broken link building, which involves finding dead pages with links and pitching your own page as a replacement.
6. Chasing brand mentions and converting unlinked mentions to linked mentions.
7. Promoting relevant brand information and getting publications to cover it.
For more link-building techniques, additional resources are recommended.

source: 7 Popular White Hat Link Building Techniques (That SEOs Are Still Using Today)