TimeMinder is a repeating interval-based app that sends users notifications (either via Sound or Vibration-only notifications) at every interval specified by the user. It is excellent for use in activities where the user needs some reminder every so often: interval focused or timed exercise, science lab experiments requiring measurements to be taken at specified intervals, standardized testing where time on questions is limited, etc.
The app also has an advanced new feature, allowing the user to "queue" up several timers before pressing "Start" to fire up several repeating interval-based timers back-to-back (successively). This can be useful in tasks that require differing repeating interval-based timers, such as timed presentation where you want to send different amounts of time on different slides.
Apple Watch support coming soon.