In the Testament of Levi found in the Dead Sea Scrolls, the 4th vault of heaven is enumerated and described as containing certain classes of Angels who continually sing praises to YHWH. These Angelic types are Thrones & Dominions.
Numerous scholars and students of angelology have concluded that Thrones are synonymous with Ophanim – or more commonly recognized as the “wheels” of Ezekiel’s vision.
Ezekiel 1:16-18
The appearance of the Ophanim and their workmanship was like sparkling beryl, and all four of them had the same form, their appearance and workmanship being as if one Ophanim were within another. Whenever they moved, they moved in any of their four directions without turning as they moved. As for their backs they were lofty and awesome, and backs of all four of them were full of sparkle round about.
To better understand Ezekiel’s vision of the Ophanim “wheels”, consider this presentation:
https://youtu.be/1EPeMotXpXk
Some assert that these beings are also called “chariots” in scripture:
Sirach 49:8
It was Ezekiel who saw the vision of glory, which God showed him above the chariot of the cherubim.
Psalms 68:17
The chariots of God are myriads, thousands upon thousands; The Lord is among them as at Sinai, in holiness.
Isaiah 66:15
For behold, the Lord will come in fire And His chariots like the whirlwind, To render His anger with fury, And His rebuke with flames of fire.
These angels who never sleep, and forever praise God, are also shown to Enoch:
Enoch 60:13-14
He shall call to every power of the heavens, to all the holy above, and to the power of God The Cherubim, the Seraphim, and the Ophanim, all the angels of power, and all the angels of Dominions, namely, of the Elect One, and of the other Power, who was upon earth over the water on that day, shall raise their united voice; shall bless, glorify, praise, and exalt with the spirit of faith, with the spirit of wisdom and patience, with the spirit of mercy, with the spirit of judgment and peace, and with the spirit of benevolence; all shall say with united voice: Blessed is He; and the name of the Lord of spirits shall be blessed for ever and for ever; all, who sleep not, shall bless it in heaven above