My solution was to design the enemy legendary creatures such that they were useful in a deck with just the one color but got better when you had access to the second color

Antiquities Square Cut (Misprinted Back) 1994 - Metal Cards, Press Checks and Production Anomalies Champions of Kamigawa Textless Cards - Metal Cards, Press Checks and Production Anomalies Fallen Empires (Wyvern Back) 1994 - Metal Cards, Press Checks and Production Anomalies Green Scrap Sheet (MTG Back) - Metal Cards, Press Checks and Production Anomalies Metal Cards - Metal Cards, Press Checks and Production Anomalies Mirage Japanese (Amstel Beer Back) - Metal Cards, Press Checks and Production Anomalies Nemesis Textless Cards - Metal Cards, Press Checks and Production Anomalies Number Cards (From Fifth Edition Simpliflied Chinese Boosters) 1998 - Metal Cards, Press Checks and Production Anomalies Pokemon German Cards Square Cut (MTG Back) 1999 - Metal Cards, Press Checks and Production Anomalies Scourge Theme Decks (Harry Potter Back) 2003 - Metal Cards, Press Checks and Production Anomalies Unlimited (Unlimited - Antiquities back) With Round Corners 1993-1994 - Metal Cards, Press Checks and Production Anomalies Urza's Destiny Textless Common Cards (Round Corners) 1999 - Metal Cards, Press Checks and Production Anomalies Urza's Destiny Textless Uncommon Cards (Round Corners) 1999 - Metal Cards, Press Checks and Production Anomalies Urza's Destiny Textless Rare Cards (Round Corners) 1999 - Metal Cards, Press Checks and Production Anomalies Urza's Destiny Textless Promos 1999 - Metal Cards, Press Checks and Production Anomalies Urza's Saga / Fourth Edition Textless Promos 1999 - Metal Cards, Press Checks and Production Anomalies

Marit Lage Marit Lage only constitutes a one-hit kill in 20-life Constructed formats, but Dark Depths has been the backbone of Lands decks in Eternal formats since the card was printed
Put those cards onto the battlefield and the rest on the bottom of your library in a random order
Boros offers many of the same incentives as White Tokens - and in fact plays many of the same powerful cards
Who said Boros was boring