How would you measure "power"? And more importantly, why would you want to know?

Grindelwald and Voldemort were strong in magic. Gellert could non-verbally parry a spell with ease (as Percival Graves), and Riddle's horcrux idea was fairly successful.

Ummmmm witch is probably Professor McGonagel (sorry I have no idea how u spell that) or Dumbledoor's mother

Wizard is Voldemort, or Dumbledoor's father

But how do u measure power?! It's really a mater if opinion

I think the most powerful wizard/ witch isn’t the one who knows all the spells and has won many battles. The most powerful wizard/witch is one who shows courage bravery kindness and is thoughtful. He/she has to show that they belong in this world. So yes most will pick Harry Potter or Dumbledore but in reality the one who should win is Neville or Ron. Neville stood up to Voldemort and used his friendship with the others to do so. Ron most of the time seemed like he was scared but in the end he was one of the bravest wizards out there. Now witches this would be Hermione or Ginny. They both showed how brave they were and that just because they were girls didn’t mean that they weren’t brave enough to be in the battles that the others were in.

I personally think that power can be measured by different ways.

But those are my own opinions and I hope you understand that everyone has different point of views.

There are lots of powerful witches throughout the wizardring history but here are SOME of them:

1)- ᏞᏆᏞᏞY ᎬᏙᎪNᏚ.

2)-ᎷᎾᏞᏞY ᏔᎬᏚᏞᎬY.

3)-ᏴᎬᏞᏞᎪᎢᎡᏆX ᏞᎬᏚᎢ ᎡᎪNᏩ.

And Also The same goes for the Wizards:

1)-ᏩᎬᏆNᎠᏞᏔᎪᏞᎠ.

2)-ᎢᎾᎷ ᎡᏆᎠᎠᏞᎬ (my favorite character).

3)-ᎷᎬᎡᏞᏆN.

(f͟͟o͟͟r͟͟g͟͟i͟͟v͟͟e͟͟ m͟͟e͟͟ f͟͟o͟͟r͟͟ m͟͟y͟͟ t͟͟e͟͟r͟͟r͟͟i͟͟b͟͟l͟͟e͟͟ s͟͟p͟͟e͟͟l͟͟l͟͟i͟͟n͟͟g͟͟,I͟͟'m͟͟ A͟͟r͟͟a͟͟b͟͟i͟͟c͟͟)

-Muggle-Born,Slytherin Alya🦑.