Quote Originally Posted by Mastocles View Post
I might be scarred from Warhammer 40K: Dark Heresy, but I would say a Hard encounter is 20–50% TPK chance —a save by DM fiat is more fun than a last minute extra minion summoning to correct for the ease of the battle.
The DMG defines Hard and Deadly as follows:
Quote Originally Posted by DMG, p. 82
Hard. A hard encounter could go badly for the adventurers. Weaker characters might get taken out of the fight, and there's a slim chance that one or more characters might die.
Deadly. A deadly encounter could be lethal for one or more player characters. Survival often requires good tactics and quick thinking, and the party risks defeat.
20-50% chance of TPK sounds more like Deadly to me. A Hard encounter might have 20-50% chance of a hireling dying, not an adventurer. I think that, for experienced players, you should just bump everything down a difficulty level. Not sure how you'd calculate what the next threshold would be, but there's probably some way to figure it out.

Quote Originally Posted by Mastocles View Post
Also, anyone know of a spreadsheet (or JSON) with some Monsters that have most of their stats? I can only find CR and type and one or two details, none with the whole set (hp, ac, abilities stats, damage parameters, etc.)
It probably doesn't exist (especially not with creatures from the MM, as that would just be C&D bait), but I could throw together something using the Basic DMG, if you'd like.