The phrase "last leg" often refers to the end of a journey or project, but there are many synonyms that can be used in its place. Some options might include "final stretch," "end game," "home stretch," "final lap," "culmination," "conclusion," "finale," "ultimate phase," "end phase," or "closing moments." Depending on the context in which the phrase is being used, some of these synonyms may be more appropriate than others. However, all of these options convey a sense of something coming to a close or being near completion, which can be useful for helping to build tension or excitement in a story or conversation.