So far we have every class covered for companions and the only races we are missing is Bosmer, Altmer, Orsimer, and Nord. I have a few suggestions for each that may fit the roles for the remaining races.
Bosmer- Thieves Guild or Dark Brotherhood skills. Create a unique rogue or assassin skills. The bonus from these could be increased Fence per day or bonus to gold from items fenced.
Altmer- Psijic Order skill line. Use some existing skills and add a few unique ones. The bonus could be Finding bonus unique items in Psijic rifts.
Orsimer- Vampire skill line. Use the existing skill line with some unique ones added. Bonus could be to reduce Vampire skill line abilities cost.
Nord- Werebear skill line. Now this one could be tricky. When not in combat they are in human form, when in combat they transform using a unique Werebear skill line similar to the werewolf. Bonus could be reduced werewolf ultimate cost.
These are just a few ideas I had and they seem to fit each Race well. Altmer for their affinity for magic, Bosmer for their stealthiness and cunning, Orsimer former clansmen of the Orc vampires in imperial city, and the Nord with their long history with the werebears in the region and Hircine.
Anyways if you either agree or disagree please leave a comment down below.