Any red commander that regularly commits crimes should consider jamming this for an easy source of mana and the occasional dragon
We know how many there are, and if we fill in the print run, we can get to percentages and odds
Amber (healing and protection), Amethyst (magic and card draw), Emerald (disruption and tempo), Ruby (aggression and high power), Sapphire (ramp and value), and Steel (removal and big bodies)
Your War of the Spark booster box contains at least one PLANESWALKER IN EVERY PACK
Lastly when your deck needs life gain you are likely a control deck or a very grindy deck
Most modern booster boxes are easy to find, but many have already accumulated value since they went out of print, so it can be difficult to make money quickly on them