Albeit being introduced for several dozens of years, multicomponent methods have yet to find widespread usage and an established position in the computational chemist toolbox. These are a unique class of quantum chemical methods, whereby electrons and a selected set of other nuclei (usually protons) are handled on the same footing. From this point onward, and for ease of discussion, we will restrict ourselves to the treatment of protons. The multicomponent methodology entails a partial lifting of the Born-Oppenheimer approximation, with selected protons being described through a wave function and coupling with the electronic solution, either through a mean-field or a more advanced description. One of the most popular denominations for the methods is the nuclearelectronic orbital (NEO) theory, which we also use to denominate our implementations.