Best multipurpose tuning app Ive heard of

Along with the tuner, this app has a drone which can play a multitude of notes, in multiple octaves at once, both in equal temperament, as well as just intonation. It also provides a great visual for your tone. While your ear is still best indicator of tone, being able to see just how bright, or dark your sound is can provide of a lot of insight. It also has an extensive metronome system built into it, with a myriad of subdivisions. This was absolutely worth the money I paid for it, and then some.

Knoxa1 about TonalEnergy Tuner & Metronome, v1.4.2