Knob Lab is described as 'offers simple yet powerful control of other iOS MIDI receiving apps, or external DAWs. Knob Lab offers simple yet powerful control of other iOS MIDI receiving apps, or external DAWs' and is an app in the Audio & Music category. There are three alternatives to Knob Lab for iPad and iPhone. The best alternative is Rozeta Sequencer Suite. Other great apps like Knob Lab are Midi Studio (Paid) and Ribn (Paid).
Ribn is a MIDI controller with 8 assignable ribbons. What makes Ribn unique is its ability to record and loop your finger movement. This allows you to add organic repeating modulation to your synths and effects, kind of like complex LFOs.