Which are not blood components that are responsible for clot formation?

Plaque is actually the buildup of fatty deposits on the artery walls which narrow and harden the arteries.  While a clot often forms around plaque, especially around a plaque rupture, it is not a part of the clotting process.  Platelets are the flat disks which stick together forming the thrombus.  Fibrin are the small strands of fiber which make up the frame work of the clot making it stronger, like reinforcing rods in concrete.  Thrombin is the protein chemo activator which signals the formation of a clotting process.