Humanities graduate theses tend to be more about analyzing sources and less about conducting empirical studies. This means that the key to developing a humanities thesis is to read about a topic that interests you. Read actively, and look for places where academics contradict themselves. Also search for questions academics raise and suggestions for further research in the conclusions of essays. All represent potential humanities topics.
Business thesis topics also can be more-specific versions of overarching themes. You can start with something such as what makes a business recession-proof, effective business management strategies or business in the context of the 2008 financial crisis.
These are not really topics, however, but are more theme-based. You could write your topic in relation to one of the themes. For the first theme, for example, you could write about two recession-proof businesses and two that suffered from a recession, including their key differences. Specificity is key in a graduate thesis.
Science theses need to address a specific issue in a scientific manner rather than in a discursive manner. The University of Virginia's Science, Technology and Society Department has a number of suggested science thesis topics online, such as resource allocation planning toolkit concept development, social norms approach for targeting the negative consequences of hazardous drinking and carbon nano ribbon-based electronics. These can be used as jumping-off points for other thesis topics by changing them slightly so you can specialize in your chosen area.
A dissertation for a doctor of philosophy degree (Ph.D.) is much longer and more in-depth than a thesis for a master's degree. Its topic needs to be much more rigidly defined and include much more background research. It is not uncommon for Ph.D. candidates to spend one or more years doing background research to define their topic; that is the typical time required to complete a master's degree. So, if you are a Ph.D. student, it is better for you to define your topic on your own rather than to seek ideas.