Best free traffic sources so far

We've launched a bit more than 2 weeks ago and since then we have about ~350 unique visitors

So far best sources of traffic were:

1. Product Hunt during launch - about 150 unique visitors during the first 2 days
2. Indie hackers (I assume mostly from product milestones) - about 8-10 visitors per day
3. Reddit (r/SideProject, r/growmybusiness etc.)
4. First results from organic search started to appear (Bing, Google)
5. GitHub since project is open source

List of websites/thread where to promote your product:
https://sizle.io/how-to-maximise-traffic-to-a-bootstrapped-product-hunt-launch/
https://www.siteguru.co/startup-directory-list