My Wife forgot her ICloud for her Apple Watch is there anyway I can trade that watch for something new?

It's the same as the iCloud account she uses on the phone it was paired with...

As for trading it in, unless you can produce the original receipt for it so that Apple can remove the activation lock for you, no. you can not trade in a device that is activation locked.

Activation Lock is designed to prevent anyone else from using an Apple Watch if it's ever lost or stolen.

About Activation Lock on your Apple Watch - Apple Support

Activation Lock is an anti-theft feature that cannot be bypassed. Only the previous owner can remove the lock by using their Apple ID & password. Apple will not help you find the previous owner. If the previous owner cannot or will not remove the lock, then the watch is useless to you or anyone else.

If you are the ORIGINAL owner, then see the 'Start a support request' section in:

How to remove Activation Lock - Apple Support

The ONLY way to remove the activation lock is using the credentials for the account that it's locked to.

She will have to recover access to that account. If she can't, it's unusable.