Both large and small projects offer valuable networking opportunities, but they serve different purposes. Contributing to large, well-known projects can give you visibility and credibility, as many people follow and engage with those repositories. However, it might be harder to get your contributions accepted due to high competition. Smaller, niche projects, on the other hand, often provide more direct access to maintainers and core contributors, which can lead to deeper relationships and learning opportunities. I recommend starting with smaller projects to build confidence and experience, and then gradually working your way up to larger ones.