Consequential Libertarianism
A.k.a. the best heuristic I can think of for capital "T" True Utilitarianism.
The problem with most utilitarianisms that I meet is that they are tied to weird, constrained views of utility maximization – they're happy to flip to double the population of Earth with 51% happiness, otherwise risk extinction, even if it means that everyone they know will die in the limit.
The problem with most libertarians that I meet is that they are so ideologically tied to the idea of freedom, and that this leads them to recommend actions that are not very conducive to freedom. For example, the "level-1" deontological libertarians is that they would recommend living in anarchy – in fact not a good way to organize society.
If they're slightly more sophisticated, they'll suggest modifications here. Perhaps true anarchy is not possible, and obviously bad. Instead, the thing that they should do is you should get as close as possible, with a centralized government there only to facilitate trade, and perform the actions in order to do so: property rights, contract enforcement, prevention of external violence. And the reasoning given is that freedom is one of those heuristics that work unreasonably well. And that any of the ways that you might want to go further to restrict freedom to allow others to pursue freedom, as some central planner, just obviously fails compared to the computational powers of the market.
In general, these sophisticated ideological libertarians would argue, optimizing to be just deontologically free gives you dividends that are very hard to predict, even for the smartest planner, a priori – freedom of speech protects democracy, say.
But, I'd argue, an ideally run society is one that instead focuses on maximizing total freedom, consequentially. In many cases, this gives you similar normative predictions to utilitarianism (and ideological libertarianism insofar that it is a strong heuristic for utilitarianism) – the thing I care about in the end is people's capacity to maximize their own welfare. For the standard second-order utilitarian reasons, you probably do both choose to switch in the trolley problem, and not to organ harvest to save five lives for everyone who enters into a hospital. In fact it probably makes sense, as a coordinating mechanism, to be deontological in the implicit social commitments you make to acting in certain ways.