Pennywise - Cross-platform application to open any website or media in a floating window
Padlet - Visual boards for organizing anything.
PiP for Mac - Always on top window preview similar to the popular windows only OnTopReplica
BookWidgets - BookWidgets is an excellent application that let you create engaging exercises in minutes and easily share a varied variety of beautiful and fun activities with your classroom and others.
PiPer - A DIY Minecraft computer to build gadgets
Quizlet - Quizlet allows you to review and create flashcards for a variety of subjects, such as math and reading.