Start your B2B lead list from the tools a website runs

Most B2B lead lists start with industry and headcount. That tells you a company exists. It doesn't tell you if your product fits.

I'd start from the software a company already runs instead. If you sell around one tool, the companies using it are the ones who'll understand your email in the first line. The fit is usually much tighter than any broad filter.

Keep it to one technology per list so the message can be specific. Write to a named founder or admin, not a generic inbox. And start small, around 100 companies, so you learn from the replies before scaling up.

If you'd rather skip the research, StackShortlist has lists of companies by the technology they use, across 3,500+ technologies: https://stackshortlist.dev