How many references should be included in the bibliography of a Master thesis?
There is no definite answer. It really depends on how much previous literature exists, how much of it you have reviewed and cited appropriately, and (loosely) what the word count of the document is. Page count can misleading, as some theses have many more figures and tables than others.

No one is going to skip to the bibliography, think negative thoughts, and say "you have too many references!" without reading the document. If no individual part of the thesis could be considered as having too many citations, then the thesis as a whole has an appropriate number of citations.

These related questions have answers as to how you can decide if a particular part of the thesis has too many citations.


Maximum number of citations per sentence?
Is there such thing as too many references for one paper?