Themes seem to arise in bidding. An odd one resurfaced for me recently -- bidding 3C as "length or shortness."
One example I have played is when partner raises my 1D opening. We have played that 3C in this sequence shows "length or shortness."
Responder then bids 3D to ask for clarification:
3H = length, this shortness
3S = length, this shortness
3NT = shortness in clubs
We are trying out a new spot for this, after transfers.
In these situations, however, Opener has two asking bids. Bidding Responder's major asks, but agrees the major as trumps. Bidding 3D also asks, suggesting clubs as trumps. Bidding the other major "asks" in a way, suggesting a 5-3 strain in that other major.
Maybe you have spots where 3C as "length or shortness" makes sense?