There is a community on the East Coast devoted to the practice of Spiritualism. While we can assume there have been people since the beginning who thought they could communicate with the dead, this particular branch originated in the 1800’s here in the U.S.
The closest I have been to anyone believing spiritualism was a couple of professor friends who were practiced Christian Science. The man died and the woman told us years later they had an agreement he would contact her in the afterlife in some specific way she did not reveal. She looked for the contact but it never came. I’ve read the Christian Science faith believes life goes on somewhat like the life before death.
The town of Lily Dale, near Buffalo, NY, is the center of Spiritualism in the U. S. People practice seances and what is called clairvoyant mediumship. Spiritualism has always endorsed science so there are people in Lily Dale experimenting with electronic amplification of contacts from the dead.
People in Lily Dale also record anomalies, things that happen to them which have no other explanation except actions taken by those who have died and are active in their lives. To a novice like myself, these anomalies sound identical to the “miracles” attributed to God in Christianity.
In the Lily Dale, NY, museum devoted to Spiritualism is an item from popular culture. We’ve all heard Elvis is still alive. The museum displays a note in Elvis’ own handwriting discussing his life after death.