Witch

Ice Prison
Frostbite: Icy exhales an icy wind at her opponent.
Iceberg: Completely freezes a surface of area.
Crystal Cage: Traps enemy in an ice container.
Arctic Blast: Releases a fragment of ice energy, focusing it, which then explodes, leaving the enemy unconscious.
Ice Coffin
Ice Crusher: A huge chunk of ice builds up next to an object and grows until the thin piece of ice holding it up breaks, causing the chunk of ice to fall on the object and crush it.
Blizzard: Creates a blizzard.
Ice Attack: Shoots a disk of crystals.
Ice Hail: Attack that wipes out everything in her path.
Ice...

The long debate of everybody wondering who is the strongest Winx club memember. Since the series has had multiple reboots, I want to focus solely on the seasons that were the most coherent and understandable. So I hope you guys are ok with my reasoning I like to say things to make them understandable and walk you through my thought process.

I remember once in season 3, they all fought Bloom to try and find weakness in the dragon fire. Stella's attack was easily beaten by Bloom, and then when Musa channeled all of her Winx into an attack, they thought it was going to work, but Bloom broke out...