The chore app "sweepy" plays a very dopaminey sound effect when you do a chore. Unfortunately, that still wasn't enough to make me keep up with using it.
It's a square wave with some amplitude shift keying. An NES could play it, so can an Arduino with a little amplifier and speaker. Sounds like a fun project! Every 100ᵗʰ press of the button could play the 1-up sound instead.
This is why I like TickTick! I have been known to undo completing a task and turning the sound back on, to complete it again when my phone was on silent, just to hear the ping.