After Queen Victoria's death, she commuted many of her incarcerated subjects. I am looking for a reference and/or a date of that.?

After Queen Victoria's death she didn't do anything, on account of being dead. Nor did the new king (Edward VII) release any prisoners. I think you have totally misheard, misread or misremembered something.

Back in the Medieval and Renaissance times when a Monarch died, their prisoners were released. This changed after Charles I so nothing was done to prisoners when Victoria died..

The only commuting of sentences (by the UK) in anything approaching modern times was the release of prisoners under the Good Friday Agreement.

How could she do anything if she was dead? and Edward VII who became King on the death of his mother did nothing with regard to prisoners either.

After her death she didn't actually do anything except decompose.

She did nothing of the sort. I think that will be why you are stuggling to find any references.