Two different questions hide in here: who points at me, and who points at my competitor. The first has an official, free answer. The second does not.
Your own site: Search Console
It is free, it is Google’s, and it shows what Google actually knows. The links report gives you the sites that point at you most, your most referenced pages, and the words used in those links.
It is the most reliable source there is for your own site, because it comes from the one deciding the position.
A competitor’s site: a third-party tool
Search Console only shows your site. To look at another, you need a tool that keeps its own index of links. The well-known ones have limited free tiers — usually enough to see a sample, and a sample is enough to understand where a competitor’s strength comes from.
What to look at, and it is not the number
Volume misleads. What is worth looking at:
- where they come from: sites in the same field, or random ones?
- how many different domains: a hundred links from one site are worth less than ten links from ten sites;
- what text they use: natural variety, or the same phrase repeated?
- how long they have existed: an old, stable link says more than a new one.
What looking at a competitor is for
Not to copy the list. It is to answer a practical question: is this fight the size I think it is? If the leaders are held up by links you could never get, the useful move is to pick a more specific term — not to chase them.