When it comes to describing something that is "most all-encompassing," there are plenty of synonyms to choose from. Some options include "comprehensive," "inclusive," "thorough," "extensive," "universal," and "complete." Each of these words conveys the idea of something that covers a wide range of topics, ideas, or concepts. Additionally, these synonyms suggest that nothing has been left out or overlooked. Whether you are describing a research project, a government policy, or a philosophical concept, using one of these synonyms can help convey the scope and importance of your subject matter.