Find New Acquisition Channels

My product: [product] built for [target audience] to solve [problem]
Channels I'm already using: [e.g. social media, word of mouth, SEO]

Brainstorm 10 acquisition channels I'm not currently using.

For each channel:
- **What it is**: Where and how it reaches users
- **Who it reaches**: The specific type of user this channel attracts
- **How to start**: A concrete action I can take in the first week
- **How to measure it**: The metric that tells me if it's working

From the 10, pick the 3 with the best combination of reach, cost, and fit for this product — and explain why the others didn't make the cut.