This app was mentioned in 5 comments, with an average of 2.60 upvotes
Try this one, quite pretty and has Play Games achievements
https://play.google.com/store/apps/details?id=com.jdamcd.sudoku
This is the one I use: https://play.google.com/store/apps/details?id=com.jdamcd.sudoku
https://play.google.com/store/apps/details?id=com.jdamcd.sudoku
https://play.google.com/store/apps/details?id=com.perunlabs.app.box
https://play.google.com/store/apps/details?id=com.martinmagni.mekorama
https://play.google.com/store/apps/details?id=com.roguetemple.hyperroidgold
https://play.google.com/store/apps/details?id=com.magmafortress.hoplite
I quite like this sudoku app.