стихотворение/ песня, где были бы слова you could/would/might have done Спасибо заранее!

Hi. When could we use the phrases such as "would have done," "could have done" and "might have done"? Do they only have be in third conditional contexts? I think a third conditional sentence is what you envision what might hypothetically have been true in the past at the present.

Some possible contexts to use these?

Do you think he did it? I think he might have done it but I am not sure.

Do you think he could have done it? I think he could have done it but I am not sure.

But I think, unlike the other two, the use of the phrase "would have been" has to be in a third condtional context.