Leading Without a Title
Some of the most effective leaders I've worked with in my career have been individual contributors. Not because they had informal authority in some abstract sense, but because they understood something specific: leadership is behavior before it is position. You do not need a title to shape a room, move an idea forward, or change how a team approaches a problem.
If you're an individual contributor (IC) who wants to grow into leadership, or who simply wants more impact where you already sit, the question isn't “how do I get promoted?” The better question is: “what would I start doing differently tomorrow?”