Includes income from renting out a property or land you own — furnished or unfurnished, long-term or short-term (including Airbnb). If you only rented out a room in your own home, the Rent-a-Room scheme may mean you have nothing to declare if your receipts were under £7,500 for the year.
This includes dividends from overseas companies or funds (US stocks, EU ETFs, etc.), foreign employment income, overseas pensions, and interest from foreign bank accounts.