It is called as the [ The Link Reclamation Strategy]
Main concept is to check any URL who has mentioned your brand name but hasn't linked back
You will need some search operators for this. Let's go one by one
intext:brand name -site:brandsite .com (This is widely used)
allinurl:tag/brand -site:yourwebsite. com (often people categorize via tagged post)
site:gov "brand" (to check any government website has mentioned )
site:edu "brand" (to check any edu site has mentioned)
intitle:brand review -site:brandsite .com (to check all the review articles & whether they have linked)
intitle:list of x things + intext:brand -site:brandsite .com (To check if they have included in their list)
Search your brand name in google images
Check all the URLs & see if they have mentioned or not ( Or Use Google Reverse Image)
To speed up the process, scrape all the URLs using Instant SERP Scraper bookmarklet.
Check 1st resource in this link for the bookmarklet.
First set up 100 results in Search results & then just click on your bookmarklet.
Drag & Drop the bookmarklet into your bookmarks tab
Then save all URLs into a google sheet
Then Under Screaming Frog Custom Search, use a regex to see if they have mentioned your brand name or not.
Read Ahref's Blog for more details of this Regex Search.
You will also need personalized outreach templates.
Type "YES" in the comments if you want the templates. I will share it.
P.S:- Subscribe to my newsletter here for more such tips on SEO & Content Marketing
very informative post for using .gov backlink