If you like puzzles then you might like to check some of these (opinions are mine, YMMV):
4 Pics 1 Word
Free. Additional clues are available by watching adverts for other games or for a payment. Guess words using the clues provided by four pictures. Various categories. Some of the puzzles in the advanced levels are very difficult.
Buttons & Scissors
Free. Remove buttons by swiping two or more buttons of the same colour in a straight line (horizontal, vertical or diagonal) with no buttons of other colours between them. A simple idea that makes for some tricky puzzles. Very colourful and very easy to operate.
Color Oil
Free. Merge blobs into one colour, by changing the colour of the current blob to that of adjacent blobs, in the least number of moves.
Flow Free
Free. Join pairs of circles of the same colour. Very colourful and very simple to use. Most of the puzzles are relatively easy so it gets somewhat repetitive.
Pop the Pic
Free. Additional clues are available by watching adverts for other games or for a payment. Guess the names objects by revealing parts of a picture. Many of the puzzles are very difficult.
Reball
Free. Move circles to form continuous lines of the same colour (horizontal, diagonal or vertical).
Rush Pipe
Free. Rotate sections of pipelines so to connect the source of water to all the outlets.
Sokoban
Free. Push blocks in a warehouse to their required positions. An excellent puzzle, but in this version the touchscreen system often results in pushing blocks too far. However, there is a multiple step undo facility.
Squarescape
Free. Move over the blue circle to collect it, then move to the exit. On each move you continue to travel until you hit a wall or other object.
Trainyard EX (Trainyard Express)
Free (there is also a more advanced version which is not free). Draw train tracks to route trains to their correct destinations. A good idea, but it gets very complicated after the first few levels.
Unblock Me FREE
Free. Slide the brown blocks out of the way so as to move the red block to the exit.