I'm sure this isn't a new idea, but hopefully this will boost the idea.
It would be super helpful to have fields that only appear when certain selections are made in other fields. I.e. If a salesperson selects ABC as their team, a dependent field appears. This field wouldn't appear if other team options are selected.
When adding custom fields, a "dependent field" checkbox would be available. When checked, you could select the parameters (field and field entry) that would trigger the field to display.