This app makes it easy to count something (reps, in my case) while using any app. If it looks familiar, it's because I previously reviewed an almost identical app that differed in how you closed the bubble and reset the count. I like the gesture based interface of this version better. The picture at right shows the settings but to be clear after you close that the green counter remains for you to position where you please. Free/no ads, but there's a paid version with more features which you should probably buy to support the developer!
Bubble Tally Counter (0.1MB, $0.0)