Here are some Scriptural accounts of relics being used for healing.
The hem of Jesus’ garment heals a woman:
“And Jesus rising up followed him, with his disciples. And behold a woman who was troubled with an issue of blood twelve years, came behind him, and touched the hem of his garment. For she said within herself: If I shall touch only his garment, I shall be healed.” Matthew 9:19-21
“And there was a certain woman having an issue of blood twelve years, who had bestowed all her substance on physicians, and could not be healed by any. She came behind him, and touched the hem of his garment; and immediately the issue of her blood stopped.” Luke 8:43-44
Peter’s shadow heals people in the streets:
“Insomuch that they brought forth the sick into the streets, and laid them on beds and couches, that when Peter came, his shadow at the least, might overshadow any of them, and they might be delivered from their infirmities.”
Acts 5:15
Paul’s handkerchiefs and aprons heal many people:
“And God wrought by the hand of Paul more than common miracles. So that even there were brought from his body to the sick, handkerchiefs and aprons, and the diseases departed from them, and the wicked spirits went out of them.” Acts 19:11-12
Clothing pieces are considered relics. (I don’t know how one would classify Peter’s shadow, but evidently it had healing properties, too.) I can’t imagine that those who were healed would have given Paul’s handkerchiefs and aprons back to him. They probably would have passed them along to other Christians who were sick. This would be one of the first instances of the use of relics - and surprise - it’s recorded in Scripture!
Oh, there are plenty of items that were used for miracles: Aaron’s rod, Gideon’s fleece, Elijah’s mantle, are examples.
The dead are to be left buried (except for relocation, such as Joseph’s command concerning himself. That’s the command and tradition of the Word. Bury them, but don’t bury something unclean in a place of worship, for heaven’s sake.
The final miracles of Elisha’s ‘double portion’ came after he was long dead, when a dead man was dropped into his tomb and came in contact with his bones. Being it was an unclean thing to handle the dead, no one is recorded to have retrived those bones to display at the temple.