EDIT: Phooey, grandmasterwang beat me to it by 8 hours (although Malagor and Morghur did have models contrary to his list, alongside Gorthor, Khazrak and Ghorros)
Oh, thought of one at last, Josef Bugman and his Rangers were missing from the Dwarf book by 8th Edition I believe - if you had their 4th Edition models as I have you could use them, but as far as I recall they weren't available in the 8th era.
And that goes for generic Rangers as well, if you wanted them different to the plastic Quarrellers you would have to get your conversion hat on.
The Kdaii almost got a model but it got changed into that big Khorne thing when they canned it. Basically the same model.
Gitilla & Snaggla are the O&G hero ones you refer to.
The only things which I can think of off the top of my head are: Ku'gath - Special character GUO. Can probably make him from the newer kit sort of. Palanquins of Nurgle options for DoC/WoC Chaos Furies - can get something approaching these from warcry Abyssal Terror mount option for VC Kholek - WoC special character Mounted Wight King BSB
Furies had models and Abyssal Terrors were the old style monstrous mount Winged Nightmares.
Malekith - on foot, Cold One, or Cold One Chariot.
Hellebron - on Manticore.
Malus Darkblade (the metal model on old "battle cattle" Cold One might have been available for some time during 8th)
Dreadlord/Master - on Dark Steed (there was an old metal model available during some of 8th, on the old "Disney Pony" Dark Steed), or on Dark Pegasus. The Cold One Chariot kit didn't technically have a specific Dreadlord/Master build instructions, but one of the crew could clearly be built as one.
Supreme Sorceress/Sorceress - on Dark Steed, or on Manticore.
Darkshards - with Shields.
Shades - with Great Weapons (though Menghil Manhide's Manflayers could be used for this), or with Additional Hand Weapons.
No BSB model existed in 8th.
Avatars of War Patreon just released a 3D print version of the Lord / Sorceress on Manticore model as well as a Sabertusk Pack.
They look cool, although you have to sign up and have 3D printing capabilities.
My armies: Empire, Dwarfs, High Elves, Wood Elves, Dark Elves, Lizardmen, Skaven, Tomb Kings, Ogre Kingdoms, Orcs and Goblins, and Skitarii (40K).