A little bit of help is needed here. I'm curious about any famous Word Bearers from before the Heresy. Things would especially be interesting if they also were known post heresy.

Could anybody post some info on these famous sons of Lorgar?

Well the novels are a great source for this, especially (False Gods?) I think has the most information about Erebus. He was the First Chaplain of the Legion at the time of the Great Crusade and was a key influence on the turn of several Legions to Chaos. Kor Phaeron was the First Captain, I believe. He was at least an extremely powerful and influential member of the Legion. The Tempus Fugitives book mentions Jarulek, the Coryphaeus to Kor Phaeron, who I know is around post-heresy for a while from the Dark Apostle and Dark Disciple books. (highly recommended, some of the best writing I have seen from the Black Library)

Chapter Master Faerskarel of the Opening Eye Chapter
Chapter Master Tenaebron of the Chapter of the Void
Chapter Master Rukis of the Crimson Mask Chapter
Chapter Master Deinos of the Burning Hand Chapter
Chapter Master Skolinthos of the Ebony Serpent Chapter
First Chaplain Erebus
First Captain Kor Phaeron
Jarulek, War Captain and Coryphaeus to the First Captain
Captain Sor Talgron of the 34th Company
Captain Argel Tal of the 7th Company
Battle Brother Khadmon (34th)
Assault Sergeant/Tactician Kol Badar(34th)
Apothecary Urhlon(34th)
Brother Sergeant Arshaq(34th)
Assault Sergeant Bachari(34th)
Sergent Paeblen(34th)
Brother Aecton(34th)

Here are some.
Sources:
Battle of the Abyss
Dark Apostle/Dark Disciple
False Gods

(assault?)captain sor talgron.

Thanks. List updated.

-Marduk: if I'm not mistaken not around before the Heresy
-Jarulek: War Captain but also Dark Apostle, if I'm not wrong he was also the Coryphaus of Kor Phaeron.
-Kol Bader: Captain during the Great Crusade, however some people mentioned he was a Sergeant (any confirmation on that please?)

sor talgron captain of the 34th company
argel tal captain of the 7th company
battle brother khadmon (34th)
assault brother sergent/tacticion kol badar(34th)
apothecary Urhlon(34th)
brother sergent Arshaq(34th)
assault sergent Bachari(34th)
Sergent paeblen(34th)
Brother Aecton(34th)

form scions of the storm.
from tales of heresy


DP

The 34th didn't participate in the invasion of Calth did they? I guess I will have to come up with my own characters then. :(

Thanks list updated.

At least 34 companies? Woah! Either Big Legion or small companies.

Does Tales of Heresy give any info on Marduk and Burias? All I know from Dark Apostle is that they fought together on Calth and that Marduk is younger than Kol Badar.

By the way, there is this odd thing in Dark Apostle, Kol Badar and Jarulek have a conversation about Marduk in which is explained that Marduk became a Space Marine at a later date, a couple of centuries later. If I'm not mistaken it also said that they've been fighting the Emperor for a couple of centuries more than Marduk, this must imply that they converted to Chaos at least a couple of centuries before the Battle of Calth/Horus Heresy right? I always assumed that their "turning sides" thing was only a couple of months/years before the actual heresy, not centuries.

Erebus is also definatly active in the 40k time period according to "Tales from the Dark Millennium"

I noticed in the tales that Sor Talgron was called "WarMonger" by the priest in "Scions of the storm".Hence the name of the dreadnaught
that Marduk talks to in "Dark Disciple".Possibly this is Sor Talgrons fate? :)
If it is indeed him, it would be a sad fate for him.Specially in a chaos dread!