Future Considerations are very prevalent in ECHL. Usually it's "I'll trade you player X and at the end of the season, we'll figure out which player Y to come back to complete the deal."
In the NHL, it's been used by teams to "give" an asset in exchange for not selecting a specific (exposed) player(s) in an expansion draft.
It's also been used to have an option to "swap" future draft picks (IOW, if team X is at position N in draft, and has the option of swapping with team Y and the position is earlier, they may execute the deal).
Heck, for all I know it may be the FC might end up being the catering bill the next time the team is in the other's city.
YMMV.