What will we wear in heaven? White robes seems to be the answer:
Revelation 7:9 After this I saw a vast crowd, too great to count, from every nation and tribe and people and language, standing in front of the throne and before the Lamb. They were clothed in white robes and held palm branches in their hands.
This particular crowd was described as having come out of suffering (also translated as dying in the great tribulation):
Revelation 7:14-17 These are the ones who came out of the great tribulation [or suffering, affliction]. They have washed their robes in the blood of the Lamb and made them white.
That is why they stand in front of God’s throne
and serve him day and night in his Temple.
And he who sits on the throne will give them shelter.
They will never again be hungry or thirsty;
they will never be scorched by the heat of the sun.
For the Lamb on the throne will be their Shepherd.
He will lead them to springs of life-giving water.
And God will wipe every tear from their eyes.
But also, people from the church in Sardis who did not return to their evil ways, and anyone who is victorious over evil, will be clothed in white:
Revelation 3:4 Yet there are some in the church in Sardis who have not soiled their clothes with evil. They will walk with me in white, for they are worthy. All who are victorious will be clothed in white.
All who have been martyred are given white robes:
Revelation 6:9-11 When the Lamb broke the fifth seal, I saw under the altar the souls of all who had been martyred for the word of God and for being faithful in their testimony. They shouted to the Lord and said, ‘O Sovereign Lord, holy and true, how long before you judge the people who belong to this world and avenge our blood for what they have done to us?’ Then a white robe was given to each of them.