Shadow of the Demon Lord: Game Mastery Critical Hit Deck.

I love Robert Schwalb's Shadow of the Demon Lord. It may be both my favorite RPG design AND my favorite RPG. It marries DnD and Warhammer's Old World, while maintaining a streamlined design that I feel is as strong as B/X DnD.

In the campaigns I've run for my group we've tried a couple of critical hit house rules, but this past session I dug out my copy of Paizo's GameMastery Critical Hit Deck for Pathfinder and it worked very well.

We only drew a card on a Natural 20.

Each card has an option for bludgeoning, piercing, slashing, and magic damage. I did have to do some conversion on the fly, but I basically just swapped Pathfinder's Saves with SotDL's Abilities and converted penalties to Banes (approximately each -2 was equal to 1 Bane).

We had a blast, with both the PC's and my NPC's scoring Crits.

I think we are going to keep using them.