This is because your Trainer Level sneakily gates a selection of Pokemon from the wild spawn pool if youre not certain levels - so the higher your Trainer Level, the more Pokmon species you can encounter
Creature - Elf Shaman Color tag templates(None) Guardian Archon Flying As this creature enters, secretly choose an opponent
Some manufacturers make cube "shells" for this very purpose, which are basically just really skinny versions of deck boxes, built to hold only 15 cards - the size of a Booster pack - at a time
If, on resolution of Nightshade Assassins EtB-trigger you only reveal Crime // Punishment, target creature will only get -1/-1, since only one card was shown
The fact that in the original games, your Mons were explicitly trained not to intentionally inflict lethal injuries might have something to do with this: a Pikachu can control how much force it puts into a Thunder Shock, but a firearm has no stun setting