Advanced Bubble users, what's a neat trick you recently discovered?

Yep, you’re 100% correct, @sudsy. There are 2 reasons that folks don’t use a custom state:

  1. They don’t know about custom states.
  2. They might be feeling lazy and don’t want to create a workflow to populate the state

… but it’s silly to use a repeating group simply to hold a reference to some list when you don’t intend to visualize anything.

Another alternative to using a custom state is to use my awesome List Shifter plugin, which one can think of as a repeating group with no visible component or a custom state will a bunch of extra utility functions on it. Since it has a field for the source list, you don’t have to execute a workflow action to populate its list. It just happens automagically on page load, just like a “hidden” repeating group. (Also, iteration.)

Aside: It kind of doesn’t matter as @nnich19’s example will not actually work. Because:

repeatinggroup coffee’s list of Coffee Blends: Item number [current cell’s index + 1]'s Caffeine content

… is not an expression that you can build (because no parens).