I was just wondering if the Lore mentions artifacts that aren't available in any games?

I was also thinking about the Daedra. You knowhow Azura hold a star and a moon: why don't we ever get Azura's crescent? The Daedra have to have more than their commonly given artifacts.

Technically they do. Because some artifacts that were available in one game are not present in other games.

I noticed many artifacts described to me in Oblivion through a book are nowhere to be found in Oblivion, but I'm sure they are in previous games. Some artifacts probably haven't been made available in any of the games yet though.

If you mean http://www.imperial-library.info/mwbooks/tamrieliclore.shtml, it's because most of them were in Morrowind.

http://www.imperial-library.info/artifacts/ is a link with all the artifacts in elder scrolls lore.

In oblivion is there a way to get artifacts without doing quests for the deadra lords?

Nope, not that I recall.

oh okay thanks

Yes there are a few..... Umbra for example... although it is in a daedric quest, it's not necesery to start it...
There is also the Cowl of the Gray Fox
The Helm of Oreyn Bearclaw, or something like that
The staff of Sheogorath
The Armor of Pelinal Whitestrake
The Draconian Madstone

Ow... what the hell... just visit this page :
http://www.uesp.net/wiki/Oblivion:Artifacts