The repository of master theses concerning the Master CS can be of use to give you inspiration regarding possible thesis topics. You can, for example, come across some interesting theses, negotiate the reference lists of those theses and learn more about which supervisors are supervising those topics.
Be conscious though that, when negotiating the repository, not all the theses are available online due to confidentiality reasons. Also be aware that the quality of the theses differ and because the grades are not mentioned this might not always become clear at first sight.
The repository of master theses CS can be issued online at: http://essay.utwente.nl/view/programme/60713.html