The most hyperbolic example is Atraxa, Grand Unifier
In a 1v1 format like Standard, giving your opponent a card so you can use the creature right away is a downside, but this blue enchantment from Bloomburrow creates the opportunity for lucrative political deals in Commander
A three mana isnt great, but this does end up with a pretty nice ability if you can get Corrupted going
Mortuary Next, lets look at a spike driven by synergy
The strategy is entirely built around the beloved warrior Yamato, offering players a highly versatile tactical toolbox that can easily adapt to changing match conditions
Though you can do better, these are worth running if you need a lot of redundancy or if you need mana dorks with activated abilities you can copy