For convenience, the Apostles are listed in the same order in which they appear in Leonardo's famous painting, The Last Supper:
Nathaniel traveled to India to preach to the people there, leaving behind a copy of the Gospel of Matthew. The king there had him beaten with rods; and after having been thus scourged, was beheaded.
James the Lesser, according to Foxs' Book of Martyrs, was beaten, stoned and clubbed to death.
Andrew "It is generally agreed that he was crucified by order of the Roman Governor, Aegeas or Aegeates, at Patrae in Achaia, and that he was bound, not nailed, to the cross, in order to prolong his sufferings” during the reign of Nero in 60 AD.
Peter It is believed that Peter was crucified upside down in Rome during the 60s.
Judas Iscariot was not a martyr. He killed himself after betraying Jesus.
John is believed to have died of natural causes, and he might have been the only Apostle to have done so. He was imprisoned along with Peter by the Jewish authorities.
Thomas was killed with a spear, according to Foxs' Book of Martyrs: "Called Didymus, preached the Gospel in Parthia and India, where exciting the rage of the pagan priests, he was martyred by being thrust through with a spear."
James The martyrdom of James son of Zebedee is recorded in the New Testament of the Bible, in Acts 12:1-2. He was executed, with a sword, by order of King Herod Agrippa I in the year 44 AD: it was about this time that King Herod arrested some who belonged to the church, intending to persecute them. He had James, the brother of John, put to death with the sword. - Acts 12:1-2. We also learn in Acts, chapter 12, that King Herod Agrippa I also imprisoned Peter for a while.
Philip was crucified, according to Foxs' Book of Martyrs: "He labored diligently in Upper Asia, and suffered martyrdom at Heliopolis, in Phrygia. He was scourged, thrown into prison, and afterwards crucified, A.D. 54."
Matthew was killed with a spear, according to Foxs' Book of Martyrs: "The scene of his labors was Parthia, and Ethiopia, in which latter country he suffered martyrdom, being slain with a halberd in the city of Nadabah, A.D. 60."
Thaddeus was crucified, according to Foxs' Book of Martyrs: "The brother of James, was commonly called Thaddeus. He was crucified at Edessa, A.D. 72."
Simon Simon was crucified, according to Foxs' Book of Martyrs: "Surnamed Zelotes, preached the Gospel in Mauritania, Africa, and even in Britain, in which latter country he was crucified, A.D. 74."
I pray we remember that this is not our final reward. And the price paid by believers who have gone before us and been martyred for their faith in Christ.