I don't know if this is impactful, but the projecy that reached out to the most people that I can think of is Mil[0]. It is a small stack-based language that I wrote in C as a learning language. I first showcased it on HN, thinking nothing much than to get feedback. It turned out to do decently well in views and reach, even reaching out to the Chinese tech community because someone posted it on a Chinese social website (I forgot the domain name).
Even though Mil's popularity is pretty typical of my other projects, but seeing it going out to other social media is pretty cool.