1) To unlock new rules or upgrade existing rules, you'll need Wisdom Nuggets.
2) Wisdom Nuggets replenish over time, so make sure you come back periodically to allocate them. They can also be found as rewards for completing certain missions, Gauntlets or events, or for donating in guilds.
Special types of Rules can only be unlocked by playing Guild Raids and obtaining Silver or Golden Nuggets. These Guild Rules give access to special, rare bonuses!