What are the best strategies to find your first 100 users for a new productivity tool?

I feel like read so many blogs, watched so many tutorials, and followed so much advice but nothing is effectively growing the SaaS start-up I work for. I'm looking for some actionable advice on how to find and attract the first 100 users. What tactics have worked best for you previously? Any tips to create genuine engagement and build a strong foundation of initial users would be appreciated!