Hackerone's Hacktivity section (https://hackerone.com/hacktivity) is an archive of vulnerability report submissions organized in a Reddit-style voting system, where the community can upvote particularly interesting reports to feature them on the section's front page:
Since reports are only made public after the bounty program manager has consented, you can see that many of them are greyed-out. But those that are visible provide a window into not only the security culture of the participating companies, but the everyday pentesting regimen of successful researchers.