Here's the huge III Corps under Ney completed.
Here is the somewhat smaller IV Corps under Bertrand.
Researching all of the new allied units proved difficult.
The first of the new troops is the 2nd Provisional Croatian Regiment. Croatia was a new part of the French Empire having been gifted to them from Austria. They had sent units to Russia in 1812 and those had had their brown Austrian uniforms replaced with new green ones in the French style, even in one case being given a French Eagle. However the 2nd Provisional was not one of these and continued into the 1813 campaign in their old brown Austrian uniforms, but with French style pom-poms and cockades on their shakos.
I decided to continue to use the French Line infantry miniatures, but painted brown and since the cockade was actually mentioned I decided rather madly to completely paint those. You can just seen in the photos that they do have all three colours, red, white and blue.
The second unit is the 3rd Baden Line Regiment. Finding information on their uniforms in 1813 was even harder, though I did find that they had replaced their helmets with French-style shakos. Their flags were easily found though.
Edit: Since posting the above someone mentioned to me that the Hesse Darmstadt unit in the 1813 German campaign did not re-organise in the French manner, only the one sent to Spain did that. So I've done a quick remodelling job to remove the colours and plumes from the grenadiers and voltigeurs...