Dear Carol:
There is not way to present a list of errant groups; there are hundred, maybe thousands.
What is a better measure is to know your Catholic Faith and test any organization or person against the truth of the Catholic Faith.
Thus, any organization that refuses to submit to the Roman Pontiff, such as the SSPX or TrueCatholic.org or fatima.org is on a errant list.
Any organization that promotes heresy or other heterodoxy, such as Catholic for Free Choice, Call to Action, and similar groups.
Here is a short list of some groups and people that are either outside of communion with the Church, heretics, heterodox dissenters against the Catholic Teachings, schismatics, or other dissenters:
SSPX (Society for St. Pius X)
Confraternity of Saints Peter and Paul
SSPV (Society of St. Pius V)
truecatholic.org
tldm.org (Last Days Ministries) (promotes Bayside visionary)
fatima.org (Fatima Network & Crusader and Fr. Gruner)
Call to Action
Catholics for a Free Choice
Andrew Greeley
bustedhalo.com
Catholic Women's Ordination
Catholic United
Commonweal Magazine
Centering Prayer
dailycatholic.org
CORPUS
Dignity (pro homosexual sex)
fisheaters.com
Maria Valtora-Poem of the Man-God (officially condemned by Vatican)
Bayside visionary Veronica Leukin (officially condemned by Vatican)
Visionary Vassula Ryden (officially condemned by Vatican)
National Catholic Reporter
novusOrdoWatch.org
Joan Chittister, OSB
Order of St. Benedict (getting into new ageism. Many Benedictine monasteries have abandon some of the charism of their founder. Many no longer kneel at the consecration, for example)
Order of Carmelites (O.Carm) (getting into new ageism. The OCD are okay)
Franciscan Order (many Franciscan communities have abandoned the charism of their founder. I personally know of one Franciscan convent that worships the goddess Sophia)
Roman Catholic Webring (the former owner of this webring once said that our website was a sorry excuse for a Catholic website and a danger to the faithful)
Voice of the Faithful
We Are Church
some of Charismatic Renewal (inasmuch as it is contaminated with Pentecostalisms)
Bishop McKenna (schismatic)
Frances Kissling (President of Catholics for a Free Choice)
Fr. Charles Curran (pro contraception)
Sex Information and Education Council for the U.S. (SIECUS)
Center for Action and Contemplation
Fr. Richard McBrien (pro women priests)
Bishop Walsh of Killaloe, Ireland (pro women priests)
Fr. Karl Rahner (opposes Transubstantiation. Beliefs Eucharist is a symbol)
Woman's Alliance for Theology, Ethics and Ritual (WATER)
Fr. Anthony De Mello (Vatican ruling which states that his teachings are incompatible with the Catholic faith and can cause grave harm)
Bishop Samual Ruiz Garcia (Liberation Theology)
Bishop Franz Kamphaus (Supports dissent via a false freedom of conscience even if contrary to Church teachings)
Hans Kung (Former theologian condemned by the Vatican)
Fr. Richard McBrien (questions the virginal conception of Jesus and our Lady's perpetual virginity, teaches that Jesus did not establish the Catholic Church, and otherwise promotes dissent)
Richard Rohr, OFM (Center for Action and Contemplation, focused on the occult Enneagram)
Bishop Remi De Roo (retired) (Supports women priests, Liberation Theology, married priests, artificial contraception)
Matthew Fox (former priest who now preaches "Creation Spirituality" He is a Supporter of Catholic Organizations for Renewal (Friends of Creation Spirituality).
Bishop Jacques Gaillot (blessed homosexual unions, supported distribution of condoms in school, opposes church teachings on contraception and divorce. He was deposed by the Holy See)
Cardinal Roger Mahoney's "Religious Education Congresses" (These conferences held each year have speakers and presenters who are often heretics or heterodox dissenters of the Church including people like Bishop Samual Ruiz Garcia, Fr. Richard Rohr, and many others)
Bishop Rembert Weakland (retired) (former Bishop of Milwaukee openly defied the Holy See by building a Cathedral contrary to Church directives. He is another dissenter)
There are MANY more, but this will give you an idea of some of the more famous ones.
God Bless,
Bro. Ignatius Mary