Looking for suggestions for websites or other channels for reaching out to users for a new product I'm working on.
Virtual events in your vertical. Plenty of people are looking to connect at events like that and you are likely able to talk to potential customers. Beyond that, just reach out to people who are possible customers on social through dm. Read Lean Customer Development and let them talk about their problem in the space. For random feedback sessions, try Lunch Club or Clubhouse.
The key is to make sure you are reaching people who could be potential customers. Here are a couple of ways I've tried:
Linkedin cold outreach. If you message 100 people that could be possible customers of your product, you're likely to get 5-10 responses.
Post to the relevant Reddit communities
Google / FB ads: This would cost money, but you basically run ad campaigns against the keywords you'd target, and send them to a landing page that has a survey form.