This is a work in progress and is probably not complete.
Use this in conjunction with other sources of information.
The main working age benefit for people with no or low incomes:
Also useful is the Social Welfare Fund
Elderly
In addition to your State Pension elderly people on low incomes may get
Got kids?
Best start grant and best start foods
Caring for someone?
Housing costs, rent
Social tariffs
Social tariffs are discounts that you can get if you're in receipt of certain means-tested benefits like Universal Credit or Pension Credit.
Useful references: