We have major two types of backlinks:
Dofollow links
Nofollow links
Dofollow links are those links that search engine counts as a vote to your website. Dofollow backlinks help your website increasing in ranking & domain authority of the website.
Nofollow links are those links that search engine doesn’t count as a vote. Nofollow links give little or no impacts on your website ranking and authority.
Moreover, one also has
Internal Links
External Links
Internal Links are links from the same domain. So when one links to other pages of his or her site or blog, they are known as internal links.
Any links from other websites or domains are termed as external links.