Take two science subjects, and that's pretty much the maximum "coverage" you can get. IB is pretty broad already, and most "arts" subjects (i.e. social sciences/humanities) don't have specific subject requirements anyway (the most common ones being Languages, History and English Lit requiring those, and Economics usually requiring some background in Maths - i.e. more than Maths Studies).
It may be worth considering that visual/performing arts subjects (music, art, drama, dance etc) usually prefer some background in that subject - either formally (a lot of music degrees require music or grade 8 theory, and many foundation art diploma programmes expect you to have some kind of art or design subject before going onto them - and hence onto a degree in the area) or informally (by assessing you through portfolio/audition - this will happen in addition to the above, but sometimes they'll assess you in this way even if you don't have formal qualifications.
I suppose the maximal coverage would be HL Chem/Phys/Maths plus whatever as your SLs - however as you're not wanting to take Maths HL, you restrict your options somewhat immediately. As you're not taking Maths, Chem/Bio would be a better pair for science subjects - certainly Chem ought to be HL if not both. However if you don't enjoy/aren't interested in sciences, and/or don't plan to apply to a related area no matter what, this is irrelevant. The main thing to bear in mind is STEM subjects at uni tend to require them (and related subjects) at 6th form (i.e. in IB for you) whereas other subjects tend not to (with some exceptions as indicated above). This may influence your choices. However you should primarily pick things you enjoy and will like working on in the coming two years - you'll have very little free time in IB, so you may as well choose work that you love - and to a lesser extent, things you're good at to maximise your results.
This is purely in terms of what degrees you could apply to, as "career" is a somewhat nebulous term, as most people will work dozens of different jobs/roles and at least 2 or 3 careers over their working life - not to mention that your degree won't necessarily have anything to do with your would be "career" (in fact, outside of specific vocations like law, engineering and medicine, as well as to some extent STEM areas generally, there are fewer jobs related to your degree than there are unrelated).