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Which Greek letters were created or adapted to represent vowel sounds?

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Thematic map of Eurasia showing the approximate geographic distribution of Indo-European language families, each represented by a different color. Areas include Celtic in western Europe, Germanic in northern and central Europe, Romance in southwestern Europe, Slavic in eastern Europe and Russia, and Indo-Iranian languages in South Asia. Non-Indo-European language regions and areas of common bilingualism are also indicated. — Greek language Approximate locations of Indo-European languages in contemporary Eurasia.

When the Greeks adapted the Phoenician alphabet to create the Greek alphabet, they made a major innovation by repurposing several Semitic consonant symbols to represent vowel sounds, which were not explicitly written in Semitic scripts.12

The following letters were adapted from Semitic consonants to represent vowels:1

Alpha ( $α$ ): Derived from the Semitic consonant alef, it was assigned the value of the vowel a.12
Epsilon ( $ϵ$ ): Derived from the Semitic consonant he, it was assigned the value of the vowel e.12
Iota ( $ι$ ): Derived from the Semitic consonant yod, it was assigned the value of the vowel i.12
Omicron ( $ο$ ): Derived from the Semitic consonant ayin, it was assigned the value of the vowel o.123
Upsilon ( $υ$ ): Derived from the Semitic consonant vav, it was assigned the value of the vowel u.12

Additionally, as the Greek alphabet evolved, further letters were created or adapted to represent specific vowel sounds, including eta ( $η$ ) for a long e ( $\bar{e}$ ) and omega ( $ω$ ) for a long o ( $\bar{o}$ ).23