The Christian group called Swedenborgian, which also now goes by the name of The New Church, rejects Paul’s writings. Many New Thought era (1860 to 1920) founded sects can be considered anti-Paulist to one degree or another: Unity, Unitarian, Christian Science, Science of Mind, Church of Divine Science, and perhaps a couple more.
There are communities to be found online who espouse (to varying degrees) a rejection of Pauline teachings. The ones I have come across appear to be founded and curated by single individuals who both write content and moderate discussions, often deleting substantive rebuttals.
Exodus 2 the Kingdom is an online blog that declares (with no subtlety) Paul to be Antichrist and rejects all Pauline writings as well as Acts, Hebrews, and much of Luke. Several months ago this blog transitioned from written to video posts and while the video posts are difficult to sit through the written posts are still accessible. Comments suggest that there are at least some folks who are in agreement. The main thrust of this blog seems to be the primacy of keeping the Law. The Ebionites (mentioned in answers and comments above) are upheld as the true Church that this blogger desires to emulate. The formative basis of this blogger's efforts appears to be a series of visions where the blogger was visited and "taken to the tree of life" while watching the "tree of Pauline doctrine" transformed into a "gnarled, blackened tree of death".
The Jesus Words Only website believes
that it is disrespectful to God, and a disgrace to ourselves, when we treat Jesus, The Prophet promised in Deuteronomy 18:18-19, as an equal or inferior to Paul who in his epistles never quotes Jesus other than the liturgy taken from Luke. See article "The Jesus' Words Only Principle Explained from Numbers 12 and Deuteronomy 18." On exactly how many times Paul uniquely quotes Jesus in his epistles regarding a lesson for us (zero times), see article Did Paul Serve Messenger Role of Christ's Words?
This appears to be a less vitriolic stance against Paul and more of a return to that transition period (during which Jesus taught) in between the Mosaic system and the institution of the Church:
The author believes that only the Law's provisions which apply to "sojourners" or "foreigners" are those intended to apply to Gentiles, viz., most of the 10 commandments are repeated as applicable to them, e.g., Sabbath observance. The author believes provisions which are stated in the Law as applicable only to Sons of Israel are thereby not applicable to Gentiles, e.g., Lev. 12:1-3 (circumcision). See Law Applicable to Gentiles. Yet, it is no sin to seek to please God by obeying such Laws, for even the Law said "sojourners" / Gentiles could participate in Passover if they were voluntarily circumcised. (Ex. 12:49.) Thus, obviously a Gentile does not sever himself from God by seeking to enjoy Jewish festivals and complying with Laws otherwise applicable only to the children of Israel. The author thus participates in Passover, and urges others to do so, as was practiced by the early church up to the 300s.
As a point of interest I have encountered hyper dispensational teaching within mainline protestant denominations. Such teaching elevates Paul's writings to a place of supreme importance to the Church and relegates the content of the gospels and the other epistles to a lesser position in that they are written to and for a different audience. It has even been proclaimed, in the name of hyper dispensation, that the New Covenant does not apply to Gentiles.
Although variations exist in specifics, all hyper-dispensationalists view the four Gospels and many of New Testament Epistles as applying to the pre-Pauline Jewish-Christian church or to the future Davidic Kingdom; not directly applicable to the predominantly Gentile Church of today.
Thus, these relatively small groups may be seen as outliers fringing both sides of the bell curve of mainstream Christian thought regarding Pauline teachings.