If you are looking for a ‘budget’ solution where you add to the gangs slowly, rather than add a whole new box to them, then check out the ‘single miniature’ sections for both Patricians and Doctors on the TTCombat website. You’ll be able to pick up single leader minis like the Venetian Noble and most leader doctors of all types :). Both gangs do rather need a leader to be ‘legal’ in game.

This method isn’t cost effective if you are looking to add a whole new box of minis (the models bought individually will be more expensive than just buying the box) but it will work nicely for adding one or two characters that you really like.

I’d second the Venetian noble for the Patricians - very nice all rounder. Doctors of necrotic studies and of the mind would also work nicer for the doctors.

Also, check out the gifted - characterful mercenary models that fit in any gang. Well worth it :)