When a empire cedes all of another empre's remaining planets into itself it sould be call an Anexation War

If a normal empire attacks a fallen empire perhaps it should be called a Giant Slayer's war or if there are multiple empires attacking a single empire it should be a gank
(Ex1: Attacking Empire - Fallen Empire Giant Slaying war)

(Ex:2 Attacking Empire - Defending Empire Gank)

Hope this helps!

I was thinking a Ultra millitarist faction with dictator or oligarchy based goverments could name wars after their leaders.

Like <Insert Leader first or Last Name here> War

Or

<Insert Leader first or Last Name here> Conflict

<Insert Leader first or Last Name here> Incident

<Insert Leader first or Last Name here> Dissagreement

fanatic purifiers can get :
purification war
extermination of (planet/species)
the great cleansing

just suggesting

@DrakenLord_52 - That's a good idea. Once I've figured out how to check wargoals, I'll add something like this.

@Senpai - I love the idea of the Giant Slayer's War. This will be in the next update.

@PBG - War names based on leaders is something I've been trying to work out for a while now. I didn't think about basing it on government type, I'll definitely give that a go.

@Spirit - Lots of nice ideas. I'll see if I can fit them in for the next update.

What about "War of the Young"?

That is a war between newly made species, like when you start the game.
I doubt it is possible though. :p

Here is some other ideas:

War of the Old (opposite of the War of the Young.)

Massacre War (when an empire attacks a civilization that do not have space technology)

Ancient War

War of Despair (when your empire is getting attacked by an Fallen Empire that hates your people)

The Great War (when two alliances (more then 3 empires) goes to war against each others)

Unwanted War (when an empire is pacifist)

Unrestricted War | War of the Joy | The Grand War (when an empire is militarist) I think you picked it up, but if you did not the war before "|" is one idea and in the middle of those 2 are another and in the end is a third.

I hope this helps you! :D

Could you add the ability to name your own wars, with perhaps a random name button?

A Great Galactic War, an equivalent to the World Wars, should be added.

A war fought with very limited wargoals could be the Attacker - Defender Incident, or the Attacker - Defender Turmoil

When a Democratic empire ask to cease the violences it could be the Attacker Intervention

Also, when a war is fought for ideology and policies (for example about the AI policy) it could be called the Attacker - Defender Ultimatum or Attacker - Defender Diktat.

When a Hive Mind or a similar collective want to annex an other empire (or many territories) it could be the Attacker Asssimilation of Defender/Territory, or the Attacker Scourge of Defender/Territory

Instead, a war against a Hive mind or a similar collective for territories could be the Disinfestation of Defender/Territory

When the main two opponents don't have any border in common it could be the Attacker - Defender Interstellar War/ Interstellar Conflict

A war started by a federation composed mostly by pacifist empires could be the Attacker Council War or Resolution War or Deliberation War

A militaristic empire that attack a bigger opponent for a territory could be the Attacker Assault on Territory

Other possible ideas/names:
.... Infestation of ...
..... - ..... Techno War / Techno War of ....
..... - ..... Galactic Unrest
..... - ..... Galactic Conflict
Galactic Rebellion/Resistence against ...
Pangalactic Defence
.... Embargo
.... - ...... War of the Hunt
..... - ..... Eugenethic War
..... - ..... Genetic War
..... - ..... Clone War

Maybe something for egalitaren spiritualist nations, maybe something like Holy Liberation War or something along those lines.

Suggestion for Hive Mind war names (Attacker/Defender):
Hive Mind/Any: [Number] Great [Attacker] Consciousness Sphere Expansion
Militarist/Hive Mind: Grand [Defender] Hunt
Fanatic Purifier/Hive Mind: Glorious [Defender] Mind Extermination
Democratic (Normal)/Hive Mind: [Defender] Taming
Democratic (Xenophile)/Hive Mind: [Defender] Mind Pacification
Technocracy or Corporate/Hive Mind: [Attacker] [Defender] Hive Exploitation Expedition
Religious (Normal or Militarist)/Hive Mind: [Attacker] War on The False God of [Defender]
Religious (Xenophobe): [Attacker] Daemonic Exorcism of [Defender]

Perhaps a liberation war of Materialists against spiritualists could be called a "Enlightening War" or "Re-Education Conflict"

[x planet] War if it is a single system being claimed

War of the [x number] Coalition or War of [x] Containment if it is multiple dudes against an empire that has expanded rapidly recently, or an awakened fallen empire

If at least half of all the empires in the galaxy are in the same war, it should be a Galactic War