A literal cone of coldness. Pretty nice, does good damage. Sadly it's a mid-late game spell. I mostly play low level campaigns

Kobolds serve dragons. You could have a white dragon's lair be filled with frozen corpses, and use a kobold sorcerer as an excuse. You should also throw in a reason as to why it's not there, because fighting a dragon AND a sorcerer of at least 9th level sounds not fun.

White dragons can technically learn the spell, also wouldn’t its breath weapon freeze creatures anyway?

Casting word is:

Freezium Grandus

You'd better believe White Draconic Sorcerers cast this from their mouths.

Since it attacks constitution, this is a good alternative to fireball when facing a high number of agile opponents.

You can always reduce the damage and area to make it a lower level spell with your DMs permission 

I've always thought that Cone of Cold should do more than just damage; its a 5th tier spell, shouldn't it cause a slow effect, or some other effect like disadvantage on dexterity saving throws? Or transform the terrain into difficult terrain (covering everything in a layer of ice that lasts until it melts)

8d8 in a 60 foot cone is a lot of damage. If you look at other damaging 5th level spells, the damage is quite a bit less. Flame Strike is 8d6, Negative Energy Flood is 5d12, etc.

Only other damaging spell that does 8d8 is Conjure Volley, and it’s ranger only.

frost fingers is kind of a level 1 version of vine of cold

Quote from Meterian >>

I've always thought that Cone of Cold should do more than just damage; its a 5th tier spell, shouldn't it cause a slow effect, or some other effect like disadvantage on dexterity saving throws? Or transform the terrain into difficult terrain (covering everything in a layer of ice that lasts until it melts)

 Cone of cold is very potent damage with a 60ft cone being a fairly large are and 8d8 cold being a large chunk of damage. If you are going to add extra effects maybe reduce the area, the damage or increase the spell level. That said I can make suggestions of spells to get effects .

• rime's binding ice  completely shut down movement 
• sleet storm  frozen ground, put out fires or obscure the area
• ray of frost reduce movement speed
• freezing sphere   freeze water

The effects from ray of frost and freezing sphere are probably the most reasonable without re balancing the spell.  You could also throw in the putting out fires pretty reasonably too.

1. Cast Cone of Cold to kill an enemy

2. Use Awakened Spellbook to swap its damage to fire using Immolation

3.  Watch everyone be confused as a massive fire cone freezes people into statues

Quote from Frozensolid333 >>

1. Cast Cone of Cold to kill an enemy

2. Use Awakened Spellbook to swap its damage to fire using Immolation

3.  Watch everyone be confused as a massive fire cone freezes people into statues

 1 and 2 logically need to be switched, but this is great. If I ever get to play a high-ish level Scribes wizard, I'm totally doing this.

Quote from Helmut_McQuack >>

Quote from Frozensolid333 >>

1. Cast Cone of Cold to kill an enemy

2. Use Awakened Spellbook to swap its damage to fire using Immolation

3.  Watch everyone be confused as a massive fire cone freezes people into statues

 1 and 2 logically need to be switched, but this is great. If I ever get to play a high-ish level Scribes wizard, I'm totally doing this.

 I've got a high scribes wiz and since I was able to get Spirit Guardians through a Strixhaven feat, I can now cast a 3d level Radiant Ball

Quote from Hoobie >>

Quote from Helmut_McQuack >>

Quote from Frozensolid333 >>

1. Cast Cone of Cold to kill an enemy

2. Use Awakened Spellbook to swap its damage to fire using Immolation

3.  Watch everyone be confused as a massive fire cone freezes people into statues

 1 and 2 logically need to be switched, but this is great. If I ever get to play a high-ish level Scribes wizard, I'm totally doing this.

 I've got a high scribes wiz and since I was able to get Spirit Guardians through a Strixhaven feat, I can now cast a 3d level Radiant Ball

 how? as far as i can tell you only gain cantrips and first level spells through the strixhaven feats

We had that NPC that wipe almost all our level 5 party with this spell.

you know what they say

Very boring, o out of 10, would not recommend

Quote from Tyranthraxes >>

Casting word is:

Freezium Grandus

 

 

Beyond 20

 

 

 

 

 

Quote from Tyranthraxes >>

Casting word is:

Freezium Grandus

 

 

Beyond 20

 

 

 

 

 

Quote from Mentleman >>

Quote from Hoobie >>

Quote from Helmut_McQuack >>

Quote from Frozensolid333 >>

1. Cast Cone of Cold to kill an enemy

2. Use Awakened Spellbook to swap its damage to fire using Immolation

3.  Watch everyone be confused as a massive fire cone freezes people into statues

 1 and 2 logically need to be switched, but this is great. If I ever get to play a high-ish level Scribes wizard, I'm totally doing this.

 I've got a high scribes wiz and since I was able to get Spirit Guardians through a Strixhaven feat, I can now cast a 3d level Radiant Ball

 how? as far as i can tell you only gain cantrips and first level spells through the strixhaven feats

 If the DM let's them get away with it?