With a moderate pull rate, Hilda offers both attainability and collectibility in equal measure
As a commander, Kefka can be ruthless, forcing your opponents to discard cards and sacrifice their permanents (whack a Tergrid in here to be extra mean)
Its about structural integrity, not just style
Obviously these may be a miss for your format for other reasons (power, archetype mismatch, rarity, don't run planeswalkers etc) but here's a few that I found interesting, divided by broad category rather than color: Actual Modal Dual Faced Cards: While I'm still not done reading Cosima, God of the Voyage (I'm on chapter 2, the language is a bit dense) these cards are ones I do like both sides of
This dwarven cleric is amazing alongside token doublers or Impact Tremors effects
Strap yourselves in and lets check out some of the most controversial cards out there