Alexander O'Neil is a renowned American R&B singer who has released numerous hit songs throughout his career. Some of his notable songs include:

1. "Criticize": Released in 1987, this song became one of O'Neil's biggest hits, reaching the top 5 on the Billboard R&B chart.
2. "If You Were Here Tonight": This soulful ballad released in 1985 remains one of O'Neil's most beloved songs.
3. "Fake": Released in 1987, this catchy track became another chart-topping hit for O'Neil.
4. "Saturday Love": A duet with Cherrelle, this song became a major success, reaching the top 10 on the Billboard R&B chart in 1985.
5. "Never Knew Love Like This": This duet with Cherrelle also achieved great success, peaking at number 2 on the Billboard R&B chart in 1988.
6. "All True Man": The title track from his 1991 album, this song showcases O'Neil's smooth vocals and soulful style.

These are just a few examples of the many incredible songs Alexander O'Neil has sung throughout his career. For a comprehensive list of his discography and further information, you can refer to his official website or music streaming platforms like Spotify or Apple Music.

Please note that the mentioned songs are subject to availability on different platforms and may vary based on your location and the time of accessing the content.