Ox takes eight cards to recast, not seven, but the raw delve numbers were never the issue
Chromatic Star, from Time Spiral Demolish, from Odyssey Flamewave Invoker, from Legions Fog Elemental, from Weatherlight Rule of Law, from Mirrodin Cho-Manno's Resolve (White) Evincar's Tyranny (Black) Arcanis's Guile (Blue) Molimo's Might (Green) Kamahl's Temper (Red)
Wall of Denial If your plan is to swing with Defenders, Wall of Denial is one of the scariest: an 8-toughness, flying Defender that can't be targeted
This means an extra land drop, another attack phase, and a whole new untap
Forgetful Fish Ben Guilfoyle explains how to play Forgetful Fish, a shared-deck, mono-blue mini-format from 1997 where players draw from one 80-card deck and race with ten Dandns
Bant/Brokers is a good color combination for adding counters and playing some politics, regardless of exactly how you do it