For example, in Modern, Scapeshift is lethal once the opponent hits seven lands, so rather than casting your discard on Turn 1, it might be better to wait until the turn before your opponent is going to kill you to give your opponent more time to draw into their key spell
Combining Gamble with effects that let you draw additional cards can mitigate the randomness of the discard
Buster Sword feels like a strong option for grinding value
It scores highly on all three of my values
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.) Except for its color, the token copies exactly what was printed on the original creature and nothing else (unless that permanent is copying something else or it is a token
Cat-Owl Cat-Owl needs to attack which is a downside, but it flies to protect itself and helps ensure you see benefits from it turn after turn