Which of the following terms best signifies everything that is real but not phenomenal?

From the Oxford English Dictionary (OED):

non-phenomenal adj.

1856 Biblical Repertory Jan. 106

It is indispensable to this scheme to deny the existence of any necessary truths. To concede it, would be to concede the knowledge of non-phenomenal entities.

1879 W. James Coll. Ess. & Rev. (1920) 94

Such relations, represented as non-phenomenal entities, become thus the bête noire and pet aversion of many thinkers.

1996 Jrnl. Philos. 93 423

It is precisely a conception of states like belief as nonphenomenal, functional states which has led to the idea that there might be zombies.

More examples:

It is best to see the main thrust of the critical philosophy as an attempt to protect non-phenomenal reality by showing that it possesses no objects that can usefully be known scientifically.
^{From The University of Western Ontario Series in Philosophy of Science Volume 24 (source)}

It could be claimed that the experience is constituted by a subject instantiating some other (non-phenomenal) property at a time. However, this option is implausible for three reasons. First, it leaves us without a way of slotting phenomenal properties into the picture. Second, it is hard to think what these other non-phenomenal properties that constitute the experience would be, and why they would be better candidates for this role than phenomenal properties.
^{Henry Taylor, 'From The relation between subjects and their conscious experiences', Philosophical Studies volume 177, pp 3493–3507 (2020) (source)}

We will call intentional states that are not phenomenal intentional states non-phenomenal intentional state.
^{From 'Phenomenal Intentionality', Stanford Encyclopedia of Philosophy (source)}

By the way, don't forget that there is also this:

noumenon: a posited object or event as it appears in itself independent of perception by the senses (Merriam-Webster)

adjective: noumenal

…separate realms (noumenal, phenomenal), and to denying that it is epistemically possible for humans to have true substantial (not merely formal) beliefs about the nature of the noumenal.
^{From David Leech, '"New Agnosticism," Imaginative Challenge, and Religious Experience', in Agnosticism: Explorations in Philosophy and Religious Thought, Francis Fallon and ‎Gavin Hyman, eds. (2020) (source)}