Modern Delver deck
Delver is a blue-based Tempo deck for the Modern format. It is usually combined with other colors for enhanced utility, most commonly Blue-White, or Red-Blue-Green a.k.a. RUG Delver.
The deck relies on playing an early threat that is large, evasive or hard to kill such as the titular Delver of Secrets, Tarmogoyf or Geist of Saint Traft, then use counterspells and removal to prevent the opponent from answering these early threats. This is helped largely by Snapcaster Mage, which helps the reuse of such utility spells and places an additional threat on the table at the same time.