Lumosity is a series of puzzle games which are easy to understand at face value which still offer a challenge and complexity. The puzzles range from testing your cognitive abilities, information processing as well as your memory. The game also offers daily challenges for those who are enthused about games like this.
I Love Hue
A colour based puzzle game, I Love Hue is as charming as the title suggests. Here you have sequences of levels all surrounding the theme of changing colour gradients from left to right or top to bottom in order to create the perfect hue. The game does get progressively more and more difficult.
Price: $3.99 (Play Store)
Probably the most famous game on this list, Monument Valley is a classic isometric 2D puzzle game in which you have to move a character by changing the viewing angle of the level and by shifting it horizontally and vertically. It also helps that the game is pleasing to the eyes and blissful.
Similar to Lumosity, Peak is also an app which has multiple games inside it. With games such as this, the bite-sized mini games is what makes them a hard recommend for people looking to kill some time, instead of the “brain developer” they are marketed as. Peak does have more variety of games in comparison with Lumosity.