To begin with, outside of STEM and the visual and performing the only courses that regularly require a specific subject to be taken before are History, English Literature, Music, various languages (requiring the named subject most of the time) and sometimes Geography, Accounting, and Economics (requiring Geography or Maths, respectively)
Psychology, Sociology, Anthropology, Classical Studies, Linguistics, Archaeology, Philosophy, Business/Management, various Cultural and Regional Studies options, Law, Religious Studies and Theology, Art History, Media and Film Studies, various technical Film and Stage Production courses, Politics, International Relations, PPE, History and Philosophy of Science in Society and related courses, Social Policy, Criminology, Journalism, Creative Writing, Quantity/Building Surveying, many more vocationally oriented IT/Computing courses (i.e. not formal Computer Science)...
I mean there are probably more courses without specific prerequisites than those with, if you go on a per subject basis. Some of the above are somewhat more uncommon (e.g. HPS and Quantity/Building Surveying) but most are fairly common courses, bordering on ubiquitous (e.g. Law or Business/Management).
There is no reason to take STEM subjects if you are not interested in them in the first instance, and frankly if you don't intend on pursuing a STEM degree, then outside of Maths there's little reason to take them at all. Maths does open up some more degree options, as it's required for some Economics/Finance/Accounting courses and preferred for a number of others (such as many PPE courses and some general Business/Management courses - also Land Economy, which only exists at Cambridge, although this may be extrapolated to Quantity/Building Surveying courses generally).