Arcademics offers skills-based games that can help you students brush up on old skills or learn new ones!
On Freerice.com, students and other users answer questions in their selected categories (ex: geography, foreign languages, English grammar, etc.) in a gamified fashion. When questions are answered correctly, the user receives a score as to how much rice they’ve donated to the World Food Programme. The number is actually a representation of how much the organization receives via ads that will be used to help support the program.
FreeTypingGame.net is an old-school typing game that reinforces typing skills.
Gimkit is an online quizzing tool that offers high engagement to older students. They are able to earn “money” (rewards) for correct answers and go “shopping” (upgrades).