Anything relating to the scam MMO known as Dreamworld that Y combinator funded, and how its funding was possibly due to nepotism.
Anything relating to the admin of KiwiFarm's rebuttal [1] of Byuu's attacks on his forum or how her suicide was proven fake.
[1] https://kiwifarms.net/threads/my-response-regarding-byuu-nea...
There are others but either I can't remember them right now or I don't have adequate sources to them.
https://news.ycombinator.com/item?id=27319457 - May 2021 (238 comments)
https://news.ycombinator.com/item?id=26898266 - April 2021 (195 comments)
Not only did we not censor that, I recall holding back on moderating it. We moderate HN less, not more, when YC or a YC-funded startup is involved (https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...).
You're right about the second case - we moderated that as not on-topic for HN.