MLPs can be a great source of rising passive income.Energy Transfer (ET 0.50%) is one of the largest, most diversified providers of energy midstream services in the country. Those assets generate lots of steady cash flow, about half of which the master limited partnership (MLP) distributes to investors. With its yield of over 8%, it's a popular income investment. Investors who like that income stream should check out fellow MLP Delek Logistics Partners (DKL 1.15%). The smaller midstream services provider cu ...