Board Thread:Skyrim/@comment-108.220.170.149-20150802214213/@comment-24873188-20150802215540

The only one I could think of that would look fitting with Nightingale and be available at Lv.25 might be the Dawnguard Rune Shield, but this is just off of personal taste. You could also get an Ebony Shield or even a Daedric shield, since they are darker colours and might fit nicely with your armour set, but can't get those until you are higher leveled. However, you can always try leveling up your smithing if at all possible. If you don't like the shields I suggested you can find them all here

The armour has Frost Resistance by 15 percent, maybe you could add another frost resist onto your shield? That or Fortify block or Illusion. You can also check for more enchantments here, if you like. Hope this helps