Two Things I Stole from Someone Else (for use in (O)D&D)

Hi, My Name is Bert the Purple Worm

The OD&D reaction roll is a 2d6, with 2-5 being negative, 6-8 uncertain and 9-12 positive. That works fine a lot of the time but then sometimes you need more information or it's just preferable to not have to think of a new way for a Gnoll to be uncertain. B/X crams additional outcomes into the role based on the rolled value but it's still not always immediately clear to me how this Gnoll reacts. Which is to say that I'm not great at spur-of-the-moment characterization.

New Rule: Designate one of the reaction roll's 2d6 "dark" and the other “light” (obviously easiest if you've got a dark and a light die, but whatever). Use the color of the higher die to determine the creature's behavior in greater detail: "dark," denotes craftiness, calculation, stalking, underhanded behavior, subterfuge while, "light," denotes forthrightness and direct action. 

Light reactions pretty clearly telegraph intent to the party: the monster is clearly unhappy with you, or its not sure or its indifferent or maybe even gestures to you for help or in some friendly greeting. The Players, of course, can still read the monster wrong.

Intelligent, calculating, outnumbered or predatory monsters are more likely to act with caution/avoid telegraphing intent so ties break “dark” for more intelligent, calculating, outnumbered or predatory creatures (if you want an editable chart listing OD&D monsterintelligence, behavior, etc., see here).

For reference, here are the results of a very simple sort and copy/paste using the linked chart.*

More Intelligent, Calculating, or Predatory Monsters

Basilisks, Chimeras, Dragons, Gargoyles, Giants, Gnolls, Goblins, Hydras, Kobolds, Medusae, Men (Bandits, Buccaneers & Nomads), Minotaurs, Ogres, Purple Worms, Sea Monsters, Trolls, Unicorns, Vampires, Weretigers, Werewolves, Wyverns

Or, if you're working with the encounter type tables on pages 17 and 18 of Volume 3 and want to do this more simply: All Dragons (less the Cockatrice), All Chaotic Giants, All odd results on the Lycanthrope table, plus Unicorns, Gargoyles, Vampires and Purple Worms (standard or marine variant). Trim to suit.

Really, though, it ought to be pretty intuitive what constitutes a more intelligent, calculating or predatory monster.

Examples of Dark Reactions by broad type

More Intelligent creatures will act as calculating, but may also use the first opportunity to alert others or try to manipulate the party for creature's own gain (EX: Dragons, Unicorns)

Calculating creatures will try to assess party strengths and weaknesses, may use poison or drugs, may lead them into traps (EX: Giants)

Predatory creatures may slink away to stalk the party or assess strengths and weaknesses (EX: Chimerae, Goblins, Werewolves)

Domesticated creatures that don't ape predatory behaviors (like a hunting animal might) - ignore Dark reactions

Motifs/Landmarks/Asks

This is a tool to help Players remind GMs things they liked/were interested in seeing more of and GMs remember those things (I sometimes fail to communicate properly with my GMs and I know I've forgotten, misplaced and mis-remembered things Players wanted to see more of).

At the start of the first session, the GM hands out index cards to the Players, one for every three players (round up, so four Players get two cards). On the cards is the word “Motif” and three bullet points. During play, each Player writes down something “in the fiction” of which they'd like to see more and initials this note. Each player can contribute one thing to a card unless numbers dictate that a Player must contribute twice to fill in all three bullets. At the end of the second session, if not earlier, all cards should be handed back to the GM.

The GM endeavors to include the three motifs in an upcoming dungeon, hex or other major location/landmark. Once done, the GM hands the Players a new card.

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*Sort by the Behavior and Organization columns. I organized each of these columns intentionally, in an order I consider more important when creating encounters and running monsters (intelligence → hunting behavior → general disposition → lairing behavior → social structure, if any, etc).

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+Epidiah Ravachol's Swords without Master does this thing where you roll 2d6, and the higher of the two rolls dictates the "tone" of the scene or next bit of the scene or whatever. I stole this from that. Motifs are used there to determine the pacing and end of the story/adventure. Here, they're much closer to an on-the-fly generator for what Necropraxis calls, "landmarks".