Link-builders, how do you find relevant blogs/websites to reach out to?

I'm currently beginning my first link-building campaign (I'm more on-page and content focused), and I'm researching relevant blogs/authors/websites in my niche to reach out to, but I'm having trouble finding relevant blogs that aren't written by my competitors.

What tools, systems, processes do you use to help you research and find relevant domains/people to reach out? Less about the email/contact info, and more just finding blogs that are covering the topic I'm interested in.

Any help is greatly appreciated!

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I mostly use Semrush, but open to other tools if they will help