Cloud, Midgar Mercenary Cloud, Midgar Mercenary is very similar to Stoneforge Mystic, and it acts as redundancy in equipment-heavy decks if you need more tutors
you can use this to your advantage to garner favor, or to cause blowouts in combat
Decks running Yawgmoth, Thran Physician can also help proliferate poison and -1/-1 counters
The effects of these particularly powerful pieces are so game changing that you're only permitted to run up one of them in your deck
For everyone else, however, some fenagling will be required
When threats are selected for their guaranteed impact on resolution, and forcing through pressure is more important than playing for card advantage, the preemptive answer of lock effects is usually the only viable option