WASD
But! I use C for crouch. When I started playing bl.. C was crouch automatically somehow. idk really. And I realized that shift is the correct button for crouch like, last year. Now I seriously can't change myself. This way I can't use D the same time as I crouch because the index finger is the one to activate them both. However, this way I can use shift, with my free little finger, for walk and thus have an easier time walking.