Tell me few brainstorming techniques

Mind-Mapping - is where you write down a central idea or problem and then create branches of related idea around it. You can add sub-branches and idea to each branch, creating a visual map of ideas and connections

Free-Writing - is where you set a timer for a specific amount of time and then write down idea that comes to mind, without stopping to edit or censor. Goal is to generate as many ideas as possible in a shortest amount of time

Role-Playing - is where you assign different roles or personas to participants in the session. Example, one person can play role of a customer, another of a competitor and so on. This help participants to see things in different perspective and generate new ideas