What is the collective nouns of victories?

There isn't a widely accepted, single, definitive collective noun for victories. However, you could use some descriptive phrases depending on the context, such as:

Formal:

* A series of triumphs

* A string of successes

* A succession of victories

Informal:

* A winning streak

* A landslide of wins

* A pile of victories

Ultimately, the best collective noun to use will depend on the specific situation and the tone you are trying to convey.