WIP, not tested within the EC sim env for functionality, but it ~should~ work. I have to go over this one more time still to set up the anode/cathode/ref I/O for a working demo.
This is a functional block diagram of the TI tl341, which is an adjustable zener. You can use these as low current shunt regulators, and, obviously, precision reference zeners. In practical application, they can be used to manage more complicated regulators (more or less, higher current/noise/dynamic handling). This is a fairly old design, but these packages are used often still as they're cheap, accurate, compact, and generally easy to work with. The only downside for the amateur is they absolutely cannot dissipate much thermal waste, nor handle more than ~100mA, even in SMD/SOT packages, these are generally less hardy than fixed zeners I'm that aspect.
