Dungeon Masters Guide and Monsters Manual
DIALS for
(i) Gritty (Lower Starting Stats, Hit Point modification*, Slower Rests, HD usage, H-Kit Dependency, Touch Attacks*** etc)
(ii) High Level (Encounter Design, Monster Modification, Higher Skill use, Setting Challenges, Terrain/Environmental Damage with engaging with creatures of sizes 2 or more than larger than you etc)
(iii) Low Magic (Spellcasting Interruption, Cantrip Limitation, Ability tied to Spellcasting Level, Magic Overexposure, Attunement modification, No Spell Focus etc)
(iv) Narrative Play (Plot Point, TBIF use/leverage, XP system modification etc)
(v) Supernatural
* Hit Point based on Size, Hit Point Cap or Health Levels
** Class Features tied to the Exhaustion Track
*** Refer Monster Design
TOOLS
Degrees of Failure/Success in Combat and Skills
Faster Combat
Gamist (Inspiration/Desperation points, Plot Points etc)
Skill Challenges
Fail Forward
Damage Severity linked to Level
Sanity (Madness, Conditions Emotional etc)
Advantage/Disadvantage (Lesser +2, Multiple)
MONSTER DESIGN
Minions and Mooks
Oozes, Mobs and Swarms
Hardness, Damage Threshold, Damage Reduction and Resistance
Regeneration
Materials Matter (Adamantine, Blessed, Silver etc)
Touch attacks for Incorporeal Creatures
OTHER
Disease Track
Magic Overexposure (Tracking, Side Effects)
Player's Handbook
ABILITIES
Class minimums
Odd numbers count
SKILLS
Subskill system
Expertise (1d6) as opposed to doubling proficiency
MODULAR
TBIF (Traits, Bonds Ideals, Flaws) system fleshed out
Languages (Expansion on Social and Exploration Pillar)
MULTI CLASS
Limitations (eliminate the 1st/2nd level dip)