Libya

Modern day Libya was known as such at least as far back as the first century as we can see from Luke's writings in the book of Acts.

Acts 2:10

Phrygia, and Pamphylia, in Egypt, and in the parts of Libya about Cyrene, and strangers of Rome, Jews and proselytes,

However, it's only ever mentioned in this one verse in the NT.

Whether Libya was referred to by the Greeks and the Romans as the land just west of Egypt, just west of the Nile, all of North Africa or all of Africa doesn't matter when it comes to analyzing OT prophesies. The only reference that matters is that of the OT writers, which wrote centuries before the Greeks and Romans conquered the area.

OT references to Libya in prophesy can be translated from various Hebrew placenames, depending upon the verse and translation used.

For example, the KJV translates Ezekiel 30:5 as

Ethiopia, and Libya, and Lydia, and all the mingled people, and Chub, and the men of the land that is in league, shall fall with them by the sword.

The NAS translates the same verse as

Ethiopia, Put, Lud, and all Arabia, Libya and the people of the land that is in league will fall with them by the sword.

The Biblios Interlintear Transliteration of Ezekiel 30:5 is as follows:

Strongs			Biblios Transliteration
3568	kūš	כּ֣וּשׁ	Ethiopia
6316	ū·p̄ūṭ	וּפ֤וּט	Put
3865	wə·lūḏ	וְלוּד֙	Lud
3605	wə·ḵāl	וְכָל־	all
6154	hā·‘e·reḇ	הָעֶ֣רֶב	Arabia
3552	wə·ḵūḇ	וְכ֔וּב	and Chub
1121	ū·ḇə·nê	וּבְנֵ֖י	and the people
776	’e·reṣ	אֶ֣רֶץ	of the land
1285	hab·bə·rîṯ	הַבְּרִ֑ית	league
854	’it·tām	אִתָּ֖ם	by
2719	ba·ḥe·reḇ	בַּחֶ֥רֶב	the sword
5307	yip·pō·lū	יִפֹּֽלוּ׃	will fall
	p̄	פ	-

So, although Libya is in both the KJV and NAS versions in this verse, it is used for two different hebrew words, put (KJV) and chub (NAS). Another OT word sometimes translated as Lybia is lubim.

So it's best to look at the specific Hebrew placenames when dealing with these ancient kingdoms.