For 180 a set of 10 duals plus some extra rainbow lands will do:

• Gainlands because it helps slow decks a little, in case they struggle a little.
• Crumbling Vestige and Ash Barrens should be less painful for aggro decks to run.

Rounded up to 20 with a utility land and the five Onslaught cycling lands, because every deck needs cantrips (?).