White Wolf materials:
There are two White Wolf released games set in medieval times...
- Vampire: The Dark Ages
while focused on vampire characters, it can easily be run for normals, using the Sorcery discipline for magic use (including additional paths from various other old-WoD supplements).
- Mage: The Sorcerer's Crusade
This one is focused upon Mages, which in the old-WoD pretty much makes them equivalent to demi-gods of legend. Still, it has some elements that make it useful for a high fantasy game.
And a couple more that can be adapted:
- Street Fighter: The Storytelling Game
Highly detailed combat rules oWoD variant. While technically modern über-powered martial arts, it can do fantasy fairly easily. Especially if you add the sorcery paths from WoD Sorcerer. Note that World Of Darkness: Combat is adapted from this one.
- Hunter: The Reckoning.
A purely Mortal game, near the end of the old WoD line; I don't have it, but have read it. Again, for mages, use WoD: Sorcerer instead of Mage. Add WoD: Combat for the same detailed combat mechanics as Street Fighter.
- World Of Darkness (New WoD core)
This is actually a generic ruleset. It can be used to do a variety of genres, but this will requires some work.
Other Dice Pools with counting successes
- Burning Wheel
An excellent game, using only d6's for the dice pool, aimed broadly at European-ish cultures circa 1200-1600. Multiple levels of combat detail, which can be slowly layered in. Current edition is Burning Wheel Gold - lovingly referred to as the "gold brick" by fans. Don't be intimidated by size; almost half of the book is lifepath options, and almost half is optional rules. General complexity higher than White Wolf's system. The truth is, tho', that BW simply checks for whether you succeeded or not - excess successes have little meaning outside of combat, and even then, far less than WW
1st edition. Out of print, hard to find. Still, an excellent dice pool game. Simple - on par with White Wolf's. 2nd Ed has a brief (1/2 page) option to use a dice pool, but that is poorly worded. Still, the rest of 2E is still compatible with the 1e dice mechanics, and is in print. Excellent setting. Unusually, the dice are rolled for low numbers being successes. Stat d6's for skill or less (with skill adjusted for difficulty). Fun combat, but pretty deadly in 1e.
- Mouse Guard
Named after the comic of the same name. Same basic task system as Burning Wheel, but streamlined and much different in the details. To quote the author, "Not ••••ing Burning Wheel Light!" Would require some adaptation for more classic fantasy... some of which has already been done. There is a free adaptation supplement for doing Rangers of the North in Middle Earth. No magic.
rules-light pick-your-favorite-kind-of-dice dice pool system. Advice on tone setting by which size of dice to use. Successes are counted against opponent's best die... so both sides can succeed with multiple successes. Interesting but not overly detailed combat. Focused mostly on the demon summoning, but the Sword & Sorcerer supplement thrusts it into classic swords and sorcery fantasy, with magic items as demons.
Dice Pools using Roll & Total
These are a roll a pool of dice (usually d6's) and total them, comparing to a target number. I don't think they're what the OP is looking for, but the ones I'm listing are pretty well regarded.
- d6 Fantasy (OOP, but PDF available free legally via RPGNow.com)
BTRC's generic system. Has excellent ability to do fantasy, tho' the various fantasy settings for it are pretty dark. Roll stat+skill dice, total the best 3.
- The One Ring
Recent offering from Cubicle 7; uses 1d12 plus (skill)d6. Has a system for counting quality of success other than just beating the TN by a large margin; each 6 rolled on the d6's increases quality of success. late 2011 offering. In print and PDF.
- Legend of the Five Rings, 7th Sea, and Legend of the Burning Sands
AEG's d10 dice pool. Roll stat+skill, keep (total) stat worth of best dice. Dice open end. Excellent, L5R in print. LBS may still be available new. Noted for strong rules/setting connections, simple mechanics, and excellent combat.
Out of print. Still, often available used. Excellent rules, but the winter rules are badly broken, unless you want everyone starving. Roll many, keep best single die, with multiples of a given die increasing the best die. 4,4,4,4 is a 7, while 4,4,5,6 is just a 6. All d6's.
- Tribe 8 (and other Silhouette System games)
Roll skill d6's, count best, but note that multiples add +1 each, in a manner similar to Orkworld. Tribe 8 is post-holocaust fantasy, with magic, and decent combat; it's the same mechanics as Heavy Gear and Jovian Chronicles, and so the vehicular and mass combat mechanics from those can easily be ported in if that's your desire. All d6's.
- Savage Worlds
Roll Stat Die + Skill Die (+1d6 if PC) and total. Well regarded generic system. Has several good fantasy settings.
- Cortex System
Roll Stat Die + Skill Die for TN+. Only called a dice pool on RPGGeek because of a poor initial definition and the pain of recalibration of the database. Note that Cortex Plus is a different engine, really, that evolved out of Cortex. Cortex's first game was Sovereign Stone; the second was Serenity; only after Serenity was the system named.
Dice Pools doing more than count successes
Not all take the one-dimensional approach of a set number of successes.
- Reign and other One-Roll Engine games.
The dice pool is rolled, and looked at for both height (what number got 2+ dice showing) and width (how many showed that number). I found it cumbersome to grasp, poorly worded, and not at all easy to use. Some swear by it, others swear at it.
Most noted for the rules for Reign for running groups and landholds.
- Warhammer FRP 3rd Edition
Note: 1st and 2nd editions are NOT dice pool systems at all!
Roll a nuber of dice, dice from stats are one type, from skill a second type, etc. (Blue attribute d8's, Red Stance d10's, Green Stance d10's, Yellow skill d6's, white boon d6's, black penalty d6's, purple resitance d8's.) Some symbols represent success, others represent side benefits, others still side effects, and others reduce success or side benefit effects. Simple, but not to everyone's tastes. Expensive, too - core box is $80 list price last I checked. Component driven, too. No numeric dice included nor used - just the symbolic ones. Substitution may be difficult.
- Houses of the Blooded & Blood and Honor
dice pool is split - some dice are rolled to see who gets to contribute, while others are set aside to determine how much one gets to contribute... Everyone who rolled 10+ on the rolled dice gets to contribute, with the highest determinging success or failure and keeping all dice set aside; others making 10+ lose half the set aside dice, while those not making 10+ lose them all. Anyone with set-aside dice gets to (in order) say one thing true about the task. This makes for very simple rules, and very fun fights. B&H, while Japanese themed, is much easier to grasp the mechanics from. HotBlooded is more machiavellian in scope, and has lots of fight-crunch, politics crunch, and funkiness. Neither is big on magic, tho'.
- Brute Squad
Warning: EXPLICITLY PVP Game
Excellent satirical game. Does some fun stuff with dice and tasks. Not for everyone. (My wife won't even consider a repeat.)
Not Fantasy, but still worth considering for adapting, various types of dice pool:
- Marvel Heroic Roleplaying (and other Cortex Plus games)
Roll many, keep 2, and level of effect is by largest type of dice left uncounted. As with many highly narrativist games, this system can easily be reskinned to fantasy. Once players grasp the dice mechanics (took about an hour when I tried it with friends online), things really started to flow. If going to Fantasy, most non-mages would have gear as one "power set" and use skills; one could add normal level skills into the mix easily (they're defined, just not used for supers); wizards would add one power set per type of magic. Magic items might be power sets of their own, as would companion animals.
- Space 1889
Available in reprint edition. Combat is roll many, count successes. Non combat is roll and total. Since it's victorian era setting, there are good rules for melee. Inspired heavily by the Martian Chronicals of Edgar Rice Boroughs... pretty much, Sword & Sorcery Fantasy with Guns and flying steamships.
- Dogs in the Vinyard
While set in "Deseret" (a historical Mormon nation that was where Utah is now), the game uses a wonky but well regarded system of pushing dice forward to make bigger totals. Without looking, I can't recall the details, but the more dice you push, the more you risk if you lose. Rules light, easily adapted to a variety of settings (several of which have been done by fans as conversion booklets).
- Prime Directive 1E aka PD One
Technically, it's a trek game. It is, however readily adapted. Dice pool is average of stat and skill. Pool is read by best single die, but noting that 6 is counted as "5 plus another die" and this recurses. I've had a character hit a 56... his initial pool was 10 dice, and he rolled a lot of 6's. The psionics rules can easily be used for magic, with only minimal changes, but they are focused on mental abilities.