Interesting to see SQL Server not listed here, am curious whether it didn't have enough signal, or suffered from being a two-word product, with "SQL" being far too generic on its own.
It is also less mentioned on the site in general, owing to it being a proprietary Microsoft product in an audience of people who primarily go for Free / Open Source non-Microsoft products. There are some people here who are interested in corporate Europe or , but most are aligned with Silicon Valley hackers.
Whereas something like Postgres has a plethora of forks and tools built around it, because it's open source devs can actually do interesting things to solve their problems.