Nice to have services: even though most of these are quite common in todays territorial monopolist states, strictly spoken none of these services is “must have”. Most of them, however, make perfect sense for sourcing them together, as a community, as they are easy to afford as a community and next to impossible to afford for the majority of citizens individually.
I’ll list a few typical “nice to have” services, each Independency should consider providing (just to give you an idea, of course, there can be more):

• Tax service: if you want to source services together, aside from the directly payed “must haves”, they won’t be free of charge, so you’ll need to have some sort of system, how the citizens finance these services; needless to say that I am sure, we as a community will be able to come up with simpler, transparent, more just systems of taxation than the current tax collectors, whose primary interest is not to finance services, but to finance a ruling elite, their staying in power, and their bureaucracy
• Social security service: unfortunately it can happen to (almost) anyone of us, to find ourselves in a situation, where it is impossible to make economic ends meet; most civilized societies therefore have some sort of social security service in place, to avoid letting fellow citizens fall into poverty;
• Generation system: everyone starts out young, in need of an education and most end up old, with the wish to retire; a well thought out and sustainable generation system makes sure, that every individual has a chance to get a top notch education, to later on be productive, innovative, and successfull to finance such a system, which in the end will also ensure, that you can afford to get old (and enjoy it); for most communities a joint generation system, providing education for the young and a chance to retire for the elderly, will make a lot of sense;
• Public health system: staying healthy (prophylaxis), naturally, should be each individuals goal and hence a goal for a community; if in individual cases this goal is not achieved, a system of public health care with best possible diagnostic and treatment services is much easier to afford for a larger group of people, than individually; so economically a joint and hence public health system of some sorts will make sense for all larger Independencies