So either you are an employer in tech industry or you can try to think as one. One may say that people are superficial but in reality people have limited time and energy to screen someone's professional competence so they have to use some reasonable heuristic, at least in the first filtering phase.
So the first websites that come to my mind are obviously Github with stars and Stackoverflow with reputation. By Github stars I mean projects with real code and not ".md awesome lists". One may argue that the most reputation on SF have answers to trivial questions, and similar for Github stars that popular projects often aren't the most valuable and I agree but on the other hand they are kind of relevant. Not often you will see really useful library with 0 stars or complete trash with 100k. Also they take years of dedication and are difficult to fake. Also Github stars are not just a badge, they are real software products and services.
And not only for employers but also for colleague developers, most of them won't dig deeply into your code but they will notice stars on repo, and form their admiration comes professional status in community.
So lets get to the point, reputation on which websites will benefit you the most? What has the most weight in real world? People have 5 minutes for initial screen of your profile and they will assign some weight to you based on something. Lets say we have 100 points in total, how many points you would assign to which website?
Websites that come to my mind are: Github stars, Stackoverflow reputation, Npm number of downloads (similar for other languages), Linkedin endorsements for technologies, Codewars scores...