This isn't creative in itself, although I'm certain one could find creative uses for it. One of the most potentially abusable spells IMO is Simulacrum. This requires a caster of at least 17th level who can cast Wish and a caster who can cast Simulacrum (or Wish, if you have two casters who can cast Wish).
1) Create a simulacrum of the 17th level wizard using Simulacrum (or Wish, if you have a second caster capable of doing so).
2) Have the simulacrum create another simulacrum of the 17th level Wizard by casting Wish.
3) Have the new simulacrum create another simulacrum. Repeat.
You now have an inexhaustible supply of high level wizards, get as creative with that as you will (Council of Ricks?).
As has been stated above, this is highly contingent on the DM allowing such shenanigans (I wouldn't), so caveat emptor.