4c Artifacts plays few creatures and relies on artifact synergies and card advantage engines like Simulacrum Synthesizer and Candy Trail, so Lightning Helix and Firebending Lesson have few profitable targets. Return the Favor can copy your own instants like Inevitable Defeat or Jeskai Revelation for extra value, and its redirect mode can point the enters trigger of their Perilous Snare or White Auracite at a less important permanent of yours. Note that it can't copy the Snare itself, since that is an artifact spell, and it only interacts with abilities and instant or sorcery spells. Outrageous Robbery provides a strong card advantage swing against a grindy, low-pressure opponent who won't punish the tempo loss. Keep Day of Judgment in since it answers any Doombot tokens or incidental creatures they generate.