In Bitcoin there's no clone terms, but fork (soft fork and hard fork) or 51% attack. Soft fork is just a development in Bitcoin, while hard fork is a fake Bitcoin e.g. BCH, BSV, WBTC etc.
WBTC is not a fork. Its a wrapped version of bitcoin. It is backed by original bitcoin with 1:1 ratio.
Look at most of the altcoins out there they only change the name but it works like Bitcoin so I consider those coins as clones of Bitcoin.
Most of the altcoins out there can be called hybrids or modified versions of bitcoin. Most of their purpose for creation was to be the better version of bitcoin that would have cheap transaction costs, more transaction speed, and be able to do what bitcoin could not. Their purpose is the same: to overthrow bitcoin, but their working structure is different. Some of them were inspired by bitcoin, while others were inspired by altcoins that were inspired by bitcoin.

There can be a few similarities, like some of them using POWs like bitcoin... but they are not identical or clone.