Here is a deep dive into what defined onion links and the "Topic" directories during that pivotal year.

In 2021, research-based lists of "20 .onion domains" often highlighted top, curated hidden services, emphasizing the transition from V2 to more secure V3 addresses. These datasets primarily categorized sites into secure communication tools, search engines, and mirrors of legitimate clearweb platforms. For a detailed academic breakdown of such a list, see the dataset hosted on ResearchGate . Dark web websites: 10 Onion sites to explore - Norton