I have an idea for a nice challenge.
Basically, you choose from one to six items.
Then you take the starting letter of every item, and you choose one Pokèmon per letter.
Say, if I choose:
Full Restore, Max Revive, Sacred Ash, Master Ball, Zap Plate.
Then I could make a team composed of:
Flareon, Metagross, Squirtle, Marshtomp, Zapdos.
They can be also non-fully evolved Pokèmon, and only one Legendary.
What do you think?