As well as the Unitarians, I have always found Quakers (or Religious Society of Friends - often shortened to Friends) to be extremely tolerant toward the religious beliefs of others. There are few other churches who would offer or allow their premises to be used by spiritualists. However, when one spiritualist church I attended had to close for a time for essential repairs, Quakers stepped in and allowed spiritualist services to be held at a Friends Meeting House.
Since 1996, every Thursday morning (between 10am - 12.30pm), except on bank holidays when it is closed, a group of spiritual healers meet in a room at The Friends Meeting House in Wakefield to give healing to the general public. All of these healers belong to a regulated healing organisation, one of which is N F S H (National Federation of Spiritual Healers) part of the Spiritualist Movement. (If you'd like to know more about the Wakefield Natural Healing Centre and the work they do not only at Friends Meeting House, Wakefield, but elsewhere then please look at the following link.)
http://www.healingwakefield.org.uk/
As well as their tolerant attitude to other religions and belief systems, I also admire the Quaker stance about non-violence and opposition to war.
Quakerism is often referred to as a mystical religion. During Quaker services, members often spend time in quiet contemplation, or meditation. Within Quaker teachings there are: Testimony of Equality, Testimony of Simplicity and Testimony of Integrity.
If you'd like to find out more about the Quaker Movement, then please open the link below so you can read a comprehensive article about the Religious Society of Friends taken from Wikipedia.
http://en.wikipedia.org/wiki/Quaker