There are a few negative elevation airfields around, I seem to recall Texel may be.
Texel is 2 feet above.
I have landed at Schiphol many times and I seem to recall it is minus 11ft.
Correct. Furthermore, Lelystad is -13ft. And my home base, Rotterdam, is even -14ft. Those are the three fields in the Netherlands that are below MSL.
But in the Netherlands we don't do QFE, just QNH so it's all a bit of a non-issue.