One of the things I've noticed looking at many products is how hard it is for people to come up with a good set of guidelines for low magic D&D.
Usually they just drop some magic items and call it good and while this is not bad, its not quite sufficient. It leaves AC far too low and as such characters are still dependent on magic items.
If you want to go "low magic" the most important thing to understand is the "rule of cancellation"
Everybody in standard D&D gets certain items as matter of course. These are colloquially called the "big six" and they are
Item of Resistance (usually a cloak)
Primary State Booster (belt, headband, gloves, etc)
Primary Defense (armor or bracers)
Booster Book (this gives an innate stat bonus)
Ring of Protection
Amulet of Natural Armor
In addition each class will probably get specific items
Warrior and Cleric Types -- magic weapons, shield
Mages -- wand or staff
Rogues -- Magic Weapon
This makes up about 80% of the standard load out of a PC.
The thing is basically they all cancel out. The bonuses to hit and spell DC from items and innate bonuses are canceled by defense bonuses .
This means you can drop the items as you wish with only two caveats
#1 Monsters. Monsters get quite a bit tougher, saves are roughly 20-30% harder (depending on bonuses) I advice simply adding 1 CR per 4 of anything with nasty magic or other save related attacks. Hopefully you won't be fighting near as many anyway.
#2 AC. Armor Class and to hit are never entirely at parity in D&D but just because you dropped the stat boosters doesn't mean the AC is quite right. What I do is add a bonus of 1/2 level round up to AC-- with half that used against flat footed, touch or other attacks, also rounded up. This puts BAB and AC back on track.
#3 1 for 1. Each magic weapons needs to either be thought of as a bonus (in which case the user is disproportionately more effective) or met with an equal defense bonus (a +3 sword met with say +3 armor)
#4 Backgrounds. I like the system in Green Ronin's work (Advanced Races/Human, Thieves World and Black Company) . Also excellent are 5th Element games
Background Levels (in which case I'd give the background feast as a bonus) and
Pathfinder Character Traits both generously shared in the Grand OGL Wiki.
#5 Extra Skill Points. Raise everyones skills by 2 (or you can use the Pathfinder rules, your choice really)
#6 Extra Feats in OGL. I use the Pathfinder Progression (1,3,5 etc) even in non Pathfinder games.
#7
Action Points. In action point dice may be used to add directly to AC.
#8 Better Stats. 25-20 point buy
Pathfinder style #9 Better Stat rolls. This isn't really just a low magic rule more of a general house rule.
One thing that always bugged me about the rules as written is the fact that a hulking brute of a fighter is only (minus his magic) maybe 20% better at battering down a door than a Wizard (STR18 vs STR10) this makes no sense to me -- Instead I'd suggest that a bonus equal to the amount over 10 be added to stat rolls. This way Big Fighter Guy (l8 fighter 20 Strength) vs Puny Mage is 50% better at the physical stuff. It also correlates nicely to the old school stat roll (stat against a D20)
And here you go, everything you need for balanced and fun low magic games in you version of D20.
