DD atmas:

Atma of the Voracious Violet (Regain+2 STR+50, Double attack+5(?%)
*Defeat Eccentric Eve, Mega-Boss for Abyssea - Konschtat.
Atma of the Razed Ruins (DEX+50 Crit.hit.Dmg+30% Crit.Hit.Rate+30%)
*Defeat Ironclad Pulverizer, Ironclad popped-NM in Abyssea Misar.
Atma of the Gnarled Horn (AGI+50 Crit.hit.Rate+30%, Counter +10%)
*Defeat Sobek, Another NM in Abyssea Misar.
Atma of the Apocalypse (Triple Attack +15%, Reraise III, Quick-magic (10% Chance to "Chainspell")
*Defeat Shinryu, Expansion Boss for Abyssea.
Atma of the Stout Arm (STR+40 Attack+50 R.atk+??)
*Defeat Briarius, "Mission" Boss for Abyssea - La'Theine.

Mage Atmas:
Atma of the Ultimate (Macc+50/Mab+50
*synthetic Atma. Created for Defeating Ultima.
Atma of the Beyond (Icedmg:+30% LightDmg:+30% MAB:+30)
*Defeat Teir III VNM in Abyssea - Kons
Atma of the Minikin Monstrosity - (Refresh+10 INT+50 Enmity-:?(30?))
*Defeat Dvalinn (Durinn?). NM in Abyssea - Vunkerl

Situational Atmas
Atma of Gales - Powers up Wind Spells 30%
Atma of Cosmos Powers up Dark spells ~40%
Atma of the Cloak and Dagger - Acc+40(?) Eva+40(?) Resist-Death
Atma of the Siren Shadow - Attack+40 Evasion +40
Atma of Dread - Treasure Hunter +1


There's Quite a few others. Focus on the DD/Mage ones, Then work on Situational Ones. Use this page:
[url]http://wiki.ffxiclopedia.org/wiki/Atma[url]
To find what you want.