A very interesting source is 100 Endgames You Must Know by Jesús de la Villa. Jesús focuses in most common endgames, with a very practical approach and only 100 pages (Spanish version) long. I miss the K+Q vs K+R ending here, but it's a very recommendable book.
More comprehensive books, and also longer and more dense, are Fundamental Chess Endings by Muller and Lampretch and Dvoretsky's Endgame Manual by Dvoretsky. I've actually used the first one to check missing endgames in de la Villa book, as the K+Q vs K+R.
These books are about theoretical endgames. Also both Dvoretsky's School of Excellence and Jacob Aagaard Grand Master Preparation series have a book each about practical endgames play. I have read none of them, so I cannot give you my impressions about them.
Another interesting book is Practical Rook Endings by Mednis, focused in rook endings that, as you know, are the most common ones.
My personal advice is to start with de la Villa Book, to have Muller or Dvoretsky's manual as a reference (at least I cannot afford to study them), and study a book about practical endings.