The Amar Kosh (ancient Sanskrit dictionary that is widely respected) defines
vibhūti
as
vibhūtir bhūtir aiśhwaryam
[v17] (power and wealth). God’s powers and wealth are unlimited. Actually, everything about him is unlimited. He has unlimited forms, unlimited names, unlimited abodes, unlimited descensions, unlimited pastimes, unlimited devotees, and so on. Hence, the Vedas refer to him by the name
anant
(unlimited)
anantaśhchātmā viśhwarūpo hyakartā
(Śhwetāśhvatar Upaniṣhad 1.9)[v18]
“God is infinite and manifests in innumerable forms in the universe. Although he administers the universe, he is yet the non-doer.” The Ramayan states
hari ananta hari kathā anantā
[v19]
“God is unlimited, and the pastimes he enacts in his unlimited
Avatārs
are also unlimited.” Sage Ved Vyas goes to the extent of saying
yo vā anantasya guṇānanantān anukramiṣhyan sa tu bāla-buddhiḥ
rajānsi bhūmer gaṇayet kathañchit kālena naivākhilaśhakti dhāmnaḥ
(Bhāgavatam 11.4.2)[v20]
“Those who think they can count the glories of God have a childish intellect. We may be successful in counting the specks of dust on the crest of the earth, but we can never count the unlimited glories of God.” Therefore, Shree Krishna says here that he will only be describing a small fraction of his
vibhūtis
.