For a consumer products, how did you get your 1st 100 users?

I’ve been building a small productivity tool and want to do some beta test soon. My previous experience only involves building and selling products to business clients, so I’m still figuring out where to target the first 100 consumer users. For those who have built and shipped consumer tool/ softaware,can you share how did you get the first 100 users? Which channels do you find useful?