The phrase "shock of rage" is a powerful description of intense anger that can feel almost physical in nature. However, there are many different synonyms that could also be used to convey this emotion. Some possibilities include "fury," "outrage," "irritation," "exasperation," "indignation," and "temper." Each of these words captures a slightly different aspect of anger, whether it be a simmering resentment or a violent eruption. Ultimately, the choice of which synonym to use will depend on the specific context and the intended tone of the writing or conversation.