I figure someone should start this page. Feel free to add and edit. I guess it should be split in to the following categories:

Viable Builds

Amazon

Javazon: Focusing mostly on Jab, Power Strike, and Charged Strike. One point in Critical Strike should be good with enough manipulation. +Jav gloves can be gambled late game.

Assassin

Trapsin: Focusing on Fire Blast and Wake of Fire. Burst of Speed is necessary to maximize FRW. +Traps weapons can be gambled late game. Lightning builds can work in 100% much better than a Fire build can. Shadow Master always like a good oskill to have for bosses.

Necromancer

Bone Necro: Focusing on Teeth, Bone Spear, and Corpse Explosion. No summons aside from oskill gear. Manipulating an early Necromancer head with +Teeth is needed and later heads can be rolled with oskill curses if need be. Bone Spirit is not as adaptable as Bone Spear is. One point in Clay Golem could help to slow down bosses in a 100%. Dim Vision will be a godsend in Hell.

Barbarian

Tank: Focusing mostly on Bash, Double Swing, and Stun. Constant manipulation of good oskill Barb helms is necessary to keep damage and leech rates high enough. +Leap Attack items can save time in certain areas of the game. Probably not good for a 100% run, but enough gear and pure weapon mastery can change this. Not for the faint of heart.

Sorceress

Lit Sorc: Focusing mostly on Lightning and Chain Lightning. This is very dependent on hitting maximum damage potential early on.

Fireball Sorc: Focusing mostly on Fire Bolt and Fireball. Very viable due to Leaf runeword. Begins to have diminishing returns in the 100%.

Meteorb Sorc: Mixes Frozen Orb with either Fireball or Meteor. Too thinly spread for an any% run, but this build is great at taking out non CI/FI mobs with relative ease in the late game.

Druid

Elementalist: Focusing on Firestorm and Fissure. No summons aside form oskill gear. Werewolf's gains in FRW do not make up for lost skill points or mana. oskill pelts are a must, though not as necessary in the early game (Firestorm is great AoE for an early spell). Jerks can get a +Hurricane pelt in 100% if they want to make things easy (and choppy).

Werewolf: Focusing on Lycanthropy and Feral Rage. With good pdsc gear, Rabies can be very beneficial for mobs. oskill pelts are a must early on. If gear is manipulated well enough, this build can work it's way in to Hell very easily.

Paladin

Zealot: Focusing on Zeal and... that's it. Auras as need be. Attack Rating becomes a limiting factor for this run. Too gear dependent for 100% unless certain runewords can be manipulated on to mercs.

Smiter: Focusing on Charge and Smite. Attack Rating is not as important here, but an emphasis on Crushing Blow is. Not viable for 100% unless you can roll the best possible items in a fast manner.

Non-viable Builds

Bowazons: Too gear dependent for normal runs, too dependent on tanks in 100% runs. Duriel would end this idea.

Kicksins: Terrible damage to speed ratios in the short run. Would be considerable for a 100% run if they had better crowd control or AoE.

Summon Necro/Fishmancer/Golemancer: No direct control over damage output in the short run. Only viable in group runs, unless a merc could somehow wear Bramble or Edge.

Singer: No dependable skills below 21, making any% very useless. Great for a 100% group run, but this build is not meant to solo without godly gear.

Enchantress: Only good with a fully synergized Enchant. Would be good for a group run, but this build can only do so much compared to other melee/support builds.

Windy Druid: No good damage until late game.

Kodiak/Werebear: Only viable as a tank until the late game, unless you consider using Shock Wave to whittle down boss hp.

Hammerdin: Too gear dependent, too mana dependent. Absolutely terrible at killing anything in Normal.

Auradin: Requires late game runewords or another Paladin to become actualized.

Speed Strategies and Techniques

Map manipulation and Scouting

Diablo II's SP map setup is unique from LAN/Bnet in that a created character uses the same map layout upon creation. Once you have entered Act I with your character, a map has already been rolled out of a large pool of possible maps. The rolled map layout is referred to as a seed. The bad thing about this is that each run will use a different map, meaning that individual planning and manipulation has to take place before playskill is considered. The good thing about this is that maps can be constantly rerolled for better layouts, shrine locations, and mob locations.

Once you have rolled a map, you will have to do an appropriate amount of scouting to ensure that the layout will breed speed and efficiency. A character's discovered map/waypoint access is located in the character save files, meaning that the unexplored map can be backed up after the character is created. Once this is done, simply playing through (or hero editing through, to save time) will determine whether or not the map is worth keeping. Once a proper map is found, make a copy of the map layouts before overwriting with the original map data.

According to suga, you can determine the map seed that your character has rolled using ATMA to read your .d2s file. Running Diablo II with the command line "-seed *" (where * is the seed number given/desired) will make all new characters bind to this map layout. Removing the command on subsequent loads will maintain the map while still allowing shrines to be altered on new segments.

Item and Shrine manipulation

All shrines aside from wells, Health, and Mana shrines are totally manipulatable (apparently). Use this to reroll the perfect sequence of shrines.

Gambling windows will refresh after every complete transaction unless another person is within a certain distance of the vendor. If a group is trying to have one person gamble, have the rest of the group fuck off. The same can be said of non-gambling manipulation, such as looking to buy pre-identified blues or imbuing certain items.

Certain chests have a much higher TC than chests around them. This should be very obvious in early Act 1 and the Countess' Tower, and these can be used to roll full potion sets, gems, or rare items for money.

Shortcut Keys

Shift click will spend all points, fill belts, and fill tomes.

Remove/equip belts to quickly shift potions to inventory, speeding up potion buying for three row belts. For two row belts (Sashes and Light Belts), quickly buying single potions is faster.

Hotkey skills when you have time to do so. Mousewheel will cycle through hotkeyed skills on the fly.

Try to keep a second gear set for a shortcut to buffs and ranged/melee tradeoffs.

Shift+number feeds your mercenary. Feed your poor mercenary and you will probably save time and money.

Shift+click makes you attack in place. Use this to keep your melee characters in their "sweet spot," or your chance to hit can plummet when a new monster gets close. You can also use this to blind fire spells without targeting enemies.

Punch Duriel in the face. Punch Infector of Souls in the face. Punch the Ancients in the face. Everyone else gets off with a slap.

Farming Areas

Cairn Stones: With proper AoE or Poison Shrines, this area can be kited up to level 6 with relative ease.

Tristram: Close proximity of Champs and Uniques makes for great leveling up to 12. Only usable in 100% runs.

Countess: Notably good exp for its location in the first act, this area becomes doubly beneficial when seeking runes from the Countess.

Inner Cloister: Bone Ash is surrounded by a minimum amount of high exp mobs and has high chances to drop great early game items.

Far Oasis: Beetleburst and his mob gives good exp up to level 18.

Canyon of the Magi/False Tombs: Great experience gains up to level 18 for non-AoE builds, and each tomb contains a high TC chest.

Flayer Jungle: Large mobs of Flayers and the like are fodder for any passing runner.

River of Flame: Hellforge always drops a rune through certain ilvl values. Manipulating these in 100% runs can make otherwise rare runes become viable.

USE JAVELINS IN ACT 1!

ALWAYS BACK UP SUCCESSFUL ATTEMPTS UNTIL YOU CAN REPLACE THEM WITH BETTER MATERIAL!

Useful Items

Runes

The earliest place for getting runes is the Countess, dropping up to Ral and generally having the highest chance for those low runes in the game. Getting a Ral from from random monster drops is impossible before some point in act 3, and even then it's way too luck-dependant. Chances to recieve one or more of the respective rune per Countess-kill in a 1-player game:

El	50.0569972%
Eld	35.7066925%
Tir	29.8937898%
Eth	21.4034589%
Nef	20.6893889%
Tal	18.0724854%
Ith	14.6487044%
Ral	12.3139942%

Chances for two fitting runes are lower than just multiplying the respective chances. When going for Tal+Eth (Stealth) and Tir+Ral (Leaf) in two runs, don't accept a segment with Tir+Eth, as Tal+Ral is much more difficult to get.

Boots

For a speedrun, it's important to run speedy. Get some boots with Faster Run/Walk. That affix doesn't spawn on magic/rare items until quite late, but there are a couple of alternatives:

Hsarus' Iron Heel (set Chain Boots): lvl 3, 30 str, 20% run, 25% fire resist

Gorefoot (unique Heavy Boots): lvl 9, 18 str, 20% run, 2% manaleech, +2 Leap (Barbarian only), other crap

With 0% magic find in a one-player game, drop chances are as follows:

Source	Hsarus	Gorefoot
Andariel (Quest)	1:92	1:140
Andariel (regular)	1:205	1:321
others	1:2000 or worse	1:4000 or worse

as both boots have their best chances at Andariel (Quest-drop), getting one or the other is feasible to manipulate. Here are some run-speeds for comparison, including the relative increases in actual run-speed by equipping the 20% boots.

type	no fr/w	20% boots		25% stealth	45% both
normal	6	6.68	+11.3%	6.84	7.36	+7.6%
lvl 1 Burst of Speed	6.52	7.2	+10.4%	7.36	7.88	+7.1%

The current Assassin Speed Run has ~55 minutes of post-Andarial gameplay. If half of that is spent running, getting fast boots would save around 2 minutes.

Sinking a second point into Burst of Speed would save roughly ~45 seconds on running, but will lose time due to reduced damage output. You could buy a claw with +1 shadow in act 2 at clvl 15 and put it on switch - if the shopping can be done fast enough, it could save a few seconds total.

Helmets

Tarnhelm: lvlreq 15, can be dropped with a chance of less than 1:800 from mephisto/diablo, can be gambled with a chance of 1:10.000. Both not viable.

rare circlet: +1 to <skilltree> has lvlreq 15, can be gambled as soon as circlets appear during gambling. Chances:

stats	lvlreq	chance when rare	chance when magic
+1 to <skilltree>	15	1:61	1:831
+1 to <skilltree>, 10% faster run	15	1:2.112	1:449.940
+1 to <skilltree>, 20% faster run	16 (!)	1:864	1:184.066
+1 to <skilltree>, any faster run	15 or 16	1:613	1:130.627

around 1 every 7 gambled items is rare. It could be imbued if white cirlets dropped anywhere early enough.

An alternative is the Nadir runeword (NefTir) for it's charges of Cloak of Shadows. CoS does not work agains act bosses, superuniques (including baal's wave bosses) and the oblivion mages in chaos sanctuary.

Gambling Amulets

What affixes are possible at what level can be seen for example here.

Amulets with +1 to <Skilltree> (i.e. +1 Traps) are wearable at clvl 15 and require ilvl (item level) 20. When gambling, the ilvl is randomly chosen between (clvl-5) and (clvl+4), so theoretically you can gamble such an amulet at clvl 16, but 9 of 10 amulets won't have the needed ilvl. When the ilvl is high enough, your chances to hit the desired skill tree are between 1:100 and 1:200.

Eye of Ettlich drops too seldom to consider (best chance: Duriel with 1:1200), and even ~1700 gambling segments (clvl 16) are quicker than 1200 Duriel kills.

In the current Assassin Speed Run, gambling a +1 trap amu would yield slightly more damage than the two synergy points from killing Izual.