Low cmc and instant speed is key here
A good example is the border around the word Deckmaster on the back of the Magic card
The version from the promo packs is more scarce than the base version, which makes it slightly more sensitive to the runaway demand
Things are improved somewhat if you look at the green version you'd be more likely to include in Keen SenseKeen Sense, but that's really just gesturing in the general direction of Glint-Horn BuccaneerGlint-Horn Buccaneer
In fact, just like the aforementioned For Mirrodin!, job select creates a creature token, although a 1/1 colorless Hero one, when the Equipment enters and it attaches said equipment to the newly created body
Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.) Casting a card by using its retrace ability works just like casting any other spell, with two exceptions: You're casting it from your graveyard rather than your hand, and you must discard a land card in addition to any other costs