One recent interesting one was Bishop James Pike - an American Episcopalian bishop in the 1960's who was on TV a fair bit and was an early advocate for the sort of church reforms which now don't sound so controversial, but were extremely so in his day. (Ordination of women, abortion, acceptance of gays fully into the church, etc.) I knew a little about him from his book The Other Side in which he claimed to have got in contact with his dead son via spiritualism. I probably read that in the paranormal-loving 1970's, and remember thinking that it sounded quite convincing. Little did I know, however, that the Bishop's personal life was a complete mess: alcoholism, affairs, and he died in a strange way in the Israeli desert. I'm pretty sure that he was fictionalised in a Philip K Dick novel too, but I forget which one.
Anyhow, I see that this week's heretic is Emanuel Swedenborg, another character I would have first read about in the 1970's, but one rarely mentioned these days. As the brief account of his life in the article notes, he was a pretty smart man in his day who went deeply off the planet into visions of angels, the afterlife and alien planets, writing at great length about his experiences and theology.
He was famous and influential in his day - Wikipedia has a lengthy article about him, including how he came to Kant's critical attention.
The Catholic Herald notes that the Churches established in his name still have about 7,000 members:
Swedenborg’s vivid writings attracted much interest, providing one strand of the 19th-century occult revival. But in 1817 a denomination was founded on them: the Swedenborgian Church of North America – which suffered a schism in 1890, forming the General Church of the New Jerusalem. Although together the two bodies today have only about 7,000 members, two American folk heroes were Swedenborgians: Johnny Appleseed and Helen Keller.I am surprised that it would even have that many members. Spiritualist and esoteric churches based on generic mysticism have never had longevity in the West - they seem too dependent on charismatic leaders holding it all together. In a way, I find that a bit sad - it's a bit of a fun fantasy to imagine that there is one small group out there that has actually Worked it All Out with complete accuracy, and it's only a matter of tracking them down.