The official online dictionary says they are: method, mode, means, plan, technique, design, system, procedure, process, measure, contrivance, stroke, step, move, action, idea, outline, plot, policy, instrument. form, fashion, gait, tone, guise, habit, custom, usage, behavior, style.
The official school Thesaurus says it’s: path, alternative, and passageway
I hope this helps you out