Do rotary incremental encoders exist that have the smooth feeling, as if turning a potentiometer? If so, does this have a name, how to identify these?
I love the flexibility of encoders in my designs, but I don't like the clunky feeling. Disclaimer: my experience is limited to two cheap encoders of Aliexpress ;-)
The clicks are called Detents. You are looking for encoders with 0 detent points, the Alps EC12E2430404 is one example.
In the case of the blue and metal 20-position rotary encoders widely available from Chinese resellers, you can actually convert the detented versions into non-detented versions.
Use needle-nose pliers to squeeze together each of the four split retaining clips (two on each side) holding the bottom and top halves together. Remove the top (metal-only) half. Use tweezers to remove the flat metal spring from that half and the tiny metal ball-bearing which creates the detent. Fit the two halves back together, re-spreading the retaining clips. And bingo, you've removed the detent-ness.
Digikey has a whole range of detent-less rotary encoders
