Hmmmm, there were several hyped gods and all but I won't include them as they don't really have much statements and stuff.
So for me it's:
1. Gaunter - :v
2. Ciri (if she could control her powers) - could stop White Frost, which is an extremely impressive feat, probably the best one shown in series
3. Vilgefortz - In full potential he could casually stomp Regis, Yen and Geralt at the same time, we are talking about a higher vampire, one of the most powerful mages in the series and probably the strongest Witcher and he is very, very versatile
4. The Unseen Elder - He is very possibly stronger than Vilgefortz, but the only things we know about him is that he roflstomped Geralt and that he is >>>>>>>>> higher vampires
5. Possibly Avallac'h/Ye (With Djinn tho, otherwise she's lower)
6. Dettlaff (monster form) - Was dancing with peak Geralt, nuff said. He's just bit stronger than Geralt and definitely faster, but of course he lost because of latters prep and overall fighting knowledge/experience.
Now I have dilemma if I should have Regis stronger than the witchers, but I think I won't, as they have counters to vampires and are more versatile.
7. Geralt - He had to be here. He is very versatile, strong and has of course most feats as he is the main character of the story. He received more mutations than other witchers so he has greater stamina, speed, most likely physical strength and reflexes than them.
8. Letho/Eskel - I have to put them on tie. Letho defeated Geralt once and he's probably physically stronger than him, but he lacks abilities and some feats. Eskel was claimed to be better than Geralt when it comes to signs and he is at very least comparable in skill, so I see Letho and Eskel being only slightly below Geralt.
9. Regis - Regis is really strong, but I believe the witchers could defeat him. He has great regenerative capabilities and is very smart, wise and fast man who could match Dettlaff
10. Villentretenmerth - strongest known dragon so he is more powerful than Saskia