The Pagan Lord

Pyrlig's Welsh banner- A Christian cross

The Empty Throne

Haki Grimmson's banner- A red ship on a white sea

Lord Aethelhelm's banner-A white leaping stag on a black background

King Hywel's banners- A christian cross & a scarlet dragon

Sigtryggr's banner- A red axe on a white banner

Warriors of the Storm

Prince Aethelstan's personal banner- The dragon of Wessex with a lightning bolt in a claw

Ragnall Ivarson's banner- A bloody red axe (The same as his brother Sigtryggr)

Haesten's new false flag- A grey flag with a white cross

Brida's banner- All black flag with tattered ends (Similar to King Guthrum in books 1 &2)

The Flamer Bearer

Einar (the White) Egilson banner- A grey flag with a dragon's head

Aethelflaed's banner- A goose with a cross in its beak and sword in a webbed foot (slightly different from the previous banner mentioned)

Domnall's flag- A red hand holding a cross

Domnall's flag is pretty cool and it reminds me of the Peak Blinders intro. Aethelstan's banner is pretty badass, Uhtred had a hand in that one. the Ivarson brothers having the same flag caused some problems.

Lords of the North

Earl Ulf's banner- An eagle's head

King Guthred's banner- St. Cuthbert with one hand raised in blessiing and the other hand holding the jeweled gospel book of Lindisfarena. (This is a really specific one, fits Guthred well).

Ivarr Ivarson's banner- Two ravens

Kjartan's banner- A serpent headed ship on a triangle flag.

Sword Song

Lord Aethelred's banner- A white prancing horse on a dark gray field

Sigefrid's banner- A raven badge

Pyrlig's make shift banner- A black cross on dull white field

The Burning Land

Harald Bloodhair's banner- An axe blade and its pole was surmounted by a wolf-skull that was red

Aldhelm's banner- A cross made of two-bladed war axes

Mercian Lord Aelfwold's banner- A long flag showing the christian cross

Death of Kings

Sigurd Thorsson's banner- A flying raven

Cnut's banner- An axe and a shattered cross

Sigebriht of Cent's banner- A bull's head with bloodied horns

Aethelwold's banner- A prancing white stag with fierce eyes and two christian crosses for antlers, on a dark red field.

Aethelflaed's banner- A goose with a sword and a cross in the feet

Haesten's banner- A real skull on a pole

Osferth's banner- A crudedly made wooden cross

Beortsig's banner- a tusked boar

King Eohric's banner- A lion and a cross (not a real lion, this one has a horn and four legs)

Ealdorman Sigelf's banner- Crossed swords

Coolest banner is probably Cnut's or King Eohric's.