Flappux - HTML based clone of Flappy Birds that is unapologetically free software.
Flying 2048 - Flying 2048... quite possibly the most "addicting" game in the world.
Tricky Sky - In Tricky Sky you must fly as far as you can while avoiding the bats.
Flappy Bird Online - Play the Original Flappy Bird Game Online.
Floculus Bird - Floculus Bird is a remake of Flappy Bird in 3D with Oculus Rift support. I made it in about five hours for Flappy Jam, a game jam organized by the indie community to show support for Dong Nguyen.
Angry Fly - Angry Fly, an 8-bit RPG Flying Adventure Around The World And Beyond