Skaven

The army from which I expected the most problems. Surprisingly, there are two Skaven ranges, one made by Mirliton and an extensive one by Black Tree Designs. I have zero experience with either company, I have however heard some bad things about Black Tree and their long delivery times, so proceed with caution. I have also heard something about Mantic working on a Skaven faction for their Kings of War, so maybe we're getting nicer models soon.

A few comments first:
  •  The models listed here are not perfect and many are not on the same level as the original ones (those are usually way older than the current GW range). I am not saying losing GW models won't be a pity, if anything this work is making me appreciate them even more. I am just saying that a solution exists. The important part is, the models are out there.
  • This is not only my work. I have used ideas and suggestions from various sources and am very grateful for the collective wisdom of the internet communities.
  • In many cases I was unsure about the size of the models and was forced to go on guesswork only. I hope at least some of them will work.
  • I am quite a chaotic person and may have overlooked something awesome. I usually try to link sites that offer greater number of useful models or the ones I know I have not exhausted, but searching around the linked models might yield even more fruit.
  • If you know about something useful not linked here, please let me know and I will add it. This is by no means an exhaustive list and can never be, but I would like to list as many possibilities as possible.

CORE

Clanrats

Black Tree Design Verman Slave Fighters (and more and command)
Mirliton Ratscum with Sword and Shield
Black Tree Design Black/Grey Horde Warriors (and some more)
Black Hat Rat Men Pirates with Swords

Giant Rats

Reaper Barrow Rats

Reaper Barrow Rats
Otherworld Miniatures Giant Rat Pack
Reaper Rats

Pack Masters

Black Tree Design Ver'man Rat Handler and Pack (and one more)

Night Runners

Reaper Wererats
Black Tree Design Vermen Sewer Runners (and more)
Otherworld Miniatures Wererats

Rat Swarm

Reaper Rat Swarm (also in Bones)
Base-of-war Vermin base
Freebooter Rat Swarms

Skaven Slaves

Reaper Wererats

Black Tree Design Verman Slave Fighters (and more)
Mantic Undead Ghoul Regiment

The ghouls could probably be painted as human slaves, driven by packmasters and mixed with rats such as these:
Black Tree Design Giant Rat Pack
Reaper Rat Swarm

Stormvermin
Black Tree Design Nest Guard Warriors (and more)
Mirliton Ratscum with Two Hand Weapons
Black Hat Rat Men Pirates with Halberds

WEAPON TEAMS - most of them would probably have to be converted, but I tried to find at least the weapons

Doom-flayer

Mantic Goblin Mincer

Or, just for fun, there is also this conversion...

Poisoned Wind Mortar
Curious Costructs Mortar
Curious Constructs Multi-mortar

Black Tree Design Ver'bombers
Mantic Abyssal Dwarf G'rog Light Mortar

Ratling Gun
Curious Constructs Gatling Gun

Warpfire Thrower

Black Tree Design Ver'burna Team (and one more)
Curious Constructs Flame Cannon
Mantic Abyssal Dwarf Dragon Fire Team

Warp Grinder
Curious Constructs Tesla Cannon

SPECIAL

Gutter Runners

Black Tree Design Ver'men Assassins

Black Tree Design Vermen Sewer Runners (and more)

Plague Censer Bearers

Black Tree Design Ver'priests

Plague Monks
Black Tree Design Ver'monks (and more)

Poison Wind Globadiers

Mantic Veer-myn Scourgers
Black Tree Design Ver'bombers

Rat Ogres

Reaper Skrattle, Giant Ratman
Black Tree Design Ver'ogre (and one more)
Black Scorpion Vermin Ogre
Impact Miniatures Willy Rat Ogre
Impact Miniatures Ratmen Wrat
Impact Miniatures Headslicer

Warplock Jezzails

Mirliton Ratscum Snipers
Mirliton Ratscum Snipers Command Group
Black Tree Design Ver'gunna (and one more)
Black Hat Rat Men Pirates With Guns

RARE

Doomwheel

Hordes Meat Thresher
Blackball Games American Tumbleweed Tank

Hell Pit Abomination

Mierce Miniatures Flint-Fang
Mierce Miniatures Three-Face

Plagueclaw Catapult

Mantic Undead Balefire Catapult
RAFM Large Catapult

Stormfiends

Mantic Veer-myn Night Spawn

Warp Lightning Cannon


Hordes Meat Thresher
Curious Constructs Tesla Cannon
Zinge Industries Tesla Coils
Abyssal Dwarf Angkor Heavy Mortar

MOUNTS

Screaming Bell

Feng Shui Bell (found in oriental shops or ebay)
This could be put on any simple construction, made from wooden sticks for mixing coffee or sprues.

Plague Furnace

Hordes Sacral Vault

Great Pox Rat

Obelisk Miniatures HumRat Scout (and more)
Mirliton Ratscum Weasel Rider

Rat Ogre Bonebreaker


Black Scorpion Vermin Ogre
Impact Miniatures Willy Rat Ogre
Impact Miniatures Ratmen Wrat
Impact Miniatures Headslicer

War-litter - would probably have to be converted, but hopefully shouldn't be too hard. And I haven't been able to find it on GW site either.

DIY conversion, tutorial here
More example conversions

CHARACTERS

Grey Seer

Black Tree Design Verlock Wizard
Reaper Wererat
Black Tree Design Wer'lock Skveek

Warlord and Chieftain

Avatars of War Vermin Clan Lord
Mierce Miniatures Blunt-Claw
Mierce Miniatures Quick-Blade
Scibor Rat Warrior
Scibor Rat Warrior

Assassin

Black Scorpion Vermin Runners

Black Tree Design Ver'men Assassins

Plague Priest
Black Tree Design Plague Shaman

Reaper Wererat

Warlock Engineer
Mantic Veer-myn Scourgers
Vermin Lord
Mierce Miniatures Scar-Scath

I recommend going through the whole Black Tree and Mirliton ranges and Black Hat Rat Men Pirates section. Black Scorpion makes a bloodbowl/fantasy football team, which might be useful as well. There are also rat heads as conversion bits, both plain and with gas masks (and some wearing Samurai helmets for those into such things). These can be put onto any model, probably including some steampunk or WWI ones. Steampunk weapons for weapon team conversions are by Curious Constructs.