Forum adverts like this one are shown to any user who is not logged in. Join us by filling out a tiny 3 field form and you will get your own, free, dakka user account which gives a good range of benefits to you: No adverts like this in the forums anymore. Times and dates in your local timezone. Full tracking of what you have read so you can skip to your first unread post, easily see what has changed since you last logged in, and easily see what is new at a glance. Email notifications for threads you want to watch closely. Being a part of the oldest wargaming community on the net. If you are already a member then feel free to login now.

Do we have the names of any of the legions prior to the finding of their respective Primarchs?

Death Guard were the Dusk Raiders, pre-primarch IIRC. It's noted by Garro in Flight of the Eisenstein.

Some of the Heresy Books refer to Legions going by their numbers - I think in Descent of Angels the Marine introduces himself as being from the '1st Legion' but not much more...