Keep calm and play on - performance book with 22 relaxing piano pieces, among others, Yann Tiersen, Yiruma and Ludovico Einaudi [music] (Electronics) 4
For me (I've been playing 15 years for hobby piano, mostly pieces of difficulty of Yiruma and co) are the pieces contained very difficult to play, but the content is great and with a little practice it should work.