http://www.humanreligions.info/tags/prayer.html
Main page:
Prayer in ReligionHuman Truth Foundation pages (13):
Does Praying for Someone Work?, in the following sections:
Prayer is Pointless, Except as Meditation, in the following sections:
God Does Not Need Prayer, Prophets, Souls, Evangelists Nor Religion, in the following sections:
Prayer is Ungodly, in the following sections:
How Does Karma Work in Hinduism, Buddhism and Jainism?: 5. Sikhism
What Does the Christian Bible say About Prayer? How Should Christians Pray?
Prayer is Magic, and Prayers are Spells: 1. Prayer is Magic
How to Pray in Islam, According to the Qur'an
The Assumptions about God and Creation, of Both Theists and Atheists: 2.9. God Communicates With Us
Not from the Human Truth Foundation, but still relevant (3):