Book 2 Monsters & Treasure: (#APP, AC, Move, HD, % in Lair, Treasure Type)
Greyhawk/Blackmoor: (#APP, AC, Move, HD, # Att, Damage, % in Lair, Treasure Type)
Monster & Treasure Assortment Set 1-3: (#APP, HP, #AT, Attack Level, AC, Saving Throw, Special Abilities, Treasure)
Village of Hommlet original cover (HP, AC, HD, Move, #ATT)
Descent into the Depths original cover (AC, Move, HD, #Att, Damage, Size)
Holmes Basic (Move, HD, AC, Treasure Type, Align, Attacks, Damage)
And its not like any of these were actually standardized. Much of the time all they cared about was Hit Points and what Treasure they might have.
Here are some later ones. This is a 2nd edition stat block from Dungeon magazine:
Then there is this dumpster fire of a stat block from 3rd edition from Dungeon magazine:
And this isn't even one of the really bad ones. No wonder players started getting frustrated with 3rd edition and all the clutter that accumulated. I don't think 4th edition made it any better.
With this info, here is a Stat Block boiled down for ease of use and essential information. The front of the card, as you can see, would be a full color illustration of a Beastie, and a description card that would come with the deck.
What do you think? Does this work for you?