Well if you're brakeless then I consider skipping, skidding, and resisting to be crucial; even if skidding is less effective its good to know and I've got out of some tight squeezes with skids.

Trackstanding is crucial for me getting the jump on cars at intersections so I can properly position myself on the road.

I think creative leaning in turns is also crucial for steering sharply in tight squeezes (throwing the bike around underneath you etc.)

Other than that nothing is really crucial