Genesis 2:18, "It is not good for man to be alone."
Single people who are alone are not good.
Genesis 2:24, "For this reason a man leaves his father and mother and embrace his wife."
This is the sole Biblical model of relationships. Any other form of relationship—including singleness—is a sinful aberration from this biblical norm.
Leviticus 15:13, "If it an emission of semen, the man must bathe his whole body in water and will be unclean until evening."
Only men who masturbate or don't have active sex lives have "emissions of semen" (wet dreams, etc.). They must be single. They are therefore unclean.
Leviticus 15:19, "A woman will unclean due to her menstruation for seven days."
Only women who are not pregnant can menstruate. She must be single. Being single—and not pregnant—leads to being unclean.
Psalm 127:3, "Children a gift from the Lord; the fruit of the womb is a divine reward."
Only non-single people can have children. Therefore if you're single—and not having children—you are not receiving a divine reward. You are not blessed.
Titus 1:6 (and 1 Tim 3:2), "Church Elders should be without fault: they should be faithful to their spouse, and have faithful children."
If you do not have a spouse or children, you are not qualified to be a leader in the church.
1 Corinthians 7:2, "Each man should have his own wife, and each woman should have her own husband because of sexual immorality."
This clearly portrays the biblical definition of sexuality immorality: not having a husband or wife. Singleness is immoral.
Now, this is clearly a cruel, inhumane, and preposterous way to read Scripture. And yet this is exactly how Scripture has been used against the LGBTQ community. Simply because much (though not all!) of Scripture assumes the primacy of hetero-family groups doesn't therefore equal the condemnation of all other kinds of families. LGBTQ people deserve better readings of the Bible.