REITs would be my first kind of company. Second would be to consider if there are closed-end or exchange-traded bond funds that could also have a high dividend stream based on the holdings of the fund.
Third would be to look at traditional companies that may offer dividends though I'd probably give some thought to whether there is an ETF of high-dividend stocks with a low expense ratio that may make it easier to hold a group of stocks to reduce individual stock risk as a single stock may change their dividend policy.
Return of capital is a risk with both closed-end funds and REITs. However, it wasn't states that the high dividends were to be safe, merely they exist.