St Bartholomew (also known as Nathaniel) was one of the first 12 Apostles. He was martyred in Armenia, but there are a bunch of stories on the way he was killed. One is that he was whipped, skinned alive and beheaded; another says that he was drowned in the sea; yet another tells of his being crucified head down.
I'm sure that there are others that I don't know.
Saint Lucy was about 21 years old when she was martyred and became a saint.
St. Vitus was martyred for his faith and early Christians considered all martyrs to be saints.
Stoned to death in front of Saul before his conversion.
Vitus was martyred about the year 303 by being boiled in oil and was probably declared a saint by the local Christian community soon afterwards.
Alexandra of Samsun was martyred about the year 300. The precise date is unknown.
Saint Nathaniel was one of the Twelve Apostles and was traditionally believed to have worked as a fisherman before being called by Jesus to be his disciple.
Both Peter and Paul were martyred in Rome.
George was martyred. He martyred no one.
Yes, he was martyred for being a Christian.
Yes, Christopher was martyred about the year 251.
Saint Agnes was martyred in Rome.
Saint Pedro Calungsod was martyred in 1672 at the age of 17.
Saint Isaac Jogues was martyred in America - Canada.
Yes, both Saint Lorenzo Ruiz and Blessed Pedro Calungsod were martyred for their faith. Saint Lorenzo Ruiz was martyred in Japan in 1637, while Blessed Pedro Calungsod was martyred in Guam in 1672. They are both revered as Filipino martyrs and saints in the Catholic Church.
Euphemia
St. Cassian
The female Christian saint martyred at Chalcedon is Saint Euphemia. She is venerated as a martyr and saint in the Eastern Orthodox, Roman Catholic, and Oriental Orthodox Churches.