this list is based on what we KNOW so far
1 Rubedo
-stated to be the strongest in nazarik, and stopped an attack that would have destroyed nazarik (with victims help)
2 Gargantua
-the strongest floor gaurdian in terms of raw power and destructive capability-
3 Pandora's actor (in touch_me's form)
shalltear is stated to be as strong as a top tier player (when fully equipped), touch_me is stated to be able to fight 3 top tier players at once and win, pandora's actor is 80% as strong as touch me when in his form (give or take) so using basic math, pandora's actor is 2.4 times stronger than shalltear when in touch_me's form (lets not talk about what would happen if he used rubedo's form)
3 Shalltear
-ainz said shalltear is the strongest floor guardean if you dont count gargantua -
4 Mare
stated by ainz to be a contender for the strongest floor guardian, and is the best with area of effect spells in among the floor guardians (despite people believing he's one of the weaker guardians he actually has stats equivalent to shalltear)
Tied 5 Sebas (Dragon Form)
-He defeated Cocytus in single combat... nuf said-
Tied 6 Cocytus
-He defeated albedo in single combat... nuf said-
Tied 7 Albedo
-Ainz said sebas might loose to albedo because of their rock paper scissors dynamic, tho she has never fought him-
8 Guren
-Ainz said, because he is a specialized combat type he's more powerful than some of the floor guardians (safe to say he means the three weakest ones)
9 Demiurge
-He is stated to be on the weaker side among the floor guardians, but he strongly believes he could beat any of the floor guardians with his superior intellect and tactical mind (but im not counting intellect as strength sooo)-
10 Aura
Alot of people seem to think demiurge is weaker than aura despite ainz straight up saying aura would be second to last in terms of power among the floor guardians and the weakest is obviously victim who has no attacks that do damage because her strength is group battle with her pets, sadly her pets dont count cus she didnt summon them with magic or anything like that she just tamed them and thus you cant count them to her own power -
Aureole would be on the list but we've never seen her fight /: