Is the list of words with a contracted "not" closed?

In this question closed means can't be added to, such as the list of pronouns, I, you, etc. can't be added to, but nouns can; a hundred years ago there was no internet or a word for fractals.

So, is the list of -n't words closed? It seems to be as you can't just attach it to any old verb. hasn't is fine but workn't isn't. I have found many lists of -n't words but none that claim to be complete, only some that say they have the commonly used words.

In this question I used three such words without realising I'd used that many! can't (three times), hasn't (my example word) and isn't.

As a rule of thumb, not only contracts with auxiliary verbs. There may be some exceptions. For example, it could be argued that in I haven't the time or the energy the verb HAVE is not an auxiliary. But note that this verb can used as an auxiliary. So we could probably reformulate that as only verbs that are sometimes auxiliaries can contract with not.

The auxiliary verbs in English are BE, HAVE, DO and the modal auxiliaries, the central members of which are:

• CAN, COULD, SHALL, SHOULD, WILL, WOULD, MAY, MIGHT and MUST

There are also a few so-called marginal auxiliaries:

• DARE, NEED, OUGHT, USED

I may have missed one or two marginal auxiliaries there.

In short, the verbs that can contract with not in English are best thought of as a small closed class. Although there is always some change on the periphery of the class (consider USED for example), the English auxiliaries are generally considered to be a closed class.