OK I'll name two: SQLite and MongoDB. I suspect that both of these are better than SQL Server on criteria I care about: ease of deployment on Linux systems, lack of issues around licensing.
Midnight Commander or Emacs is better than SQL Server if those are the criteria you care about.
Have you ever used SQL server and do you know what type of problems it aims to solve?
I'm probably working in different environment than you, because I have never seen SQL Server used, when we want something with support we use Oracle.