Daniel Wright, 29, Liam Hall, 31, and Stacey Salmon, 29, all from Keighley, West Yorkshire, and Samuel Whibley, 29, from Menai Bridge, Anglesey, had denied the charges.
During the trial prosecutors said the four “celebrated racist violence and killing” through online messages.
They will be sentenced at a later date.
A two-month trial, which was moved to Doncaster Crown Court due to problems at Sheffield Crown Court, heard the defendants used online messaging app Telegram to exchange terror manuals, share racist ideology and post videos of atrocities.
Prosecutor Annabel Darlow QC said the group described killers such as Oklahoma City bomber Timothy McViegh and Anders Breivik, who murdered 77 people in Norway, as “saints.
She told jurors the group also had an “active interest in the manufacture of explosives and weaponry”.
Daniel Wright, of Whinfield Avenue, Keighley, was found guilty of disseminating a terrorist publication, possessing articles for terrorist purposes, and the collection of information contrary to the Terrorism Act.
He was also found guilty of possessing and manufacturing a firearm.
Liam Hall, of Hill Top Walk, Keighley, was cleared of possessing articles for terrorist purposes, but found guilty of possessing and manufacturing a firearm.
Hall’s partner Stacey Salmon, of the same address, was also cleared of possessing articles for terrorist purposes, but convicted of possessing a firearm.
Samuel Whibley, of Derwen Deg, Menai Bridge, Anglesey, was found guilty of the encouragement of terrorism and disseminating a terrorist publication.
