Partly - That is, your affliction consisted partly in this. The Greek is, "this" - specifying one kind of affliction that they were called to endure.

Whilst ye were made a gazing-stock - Greek θεατριζόμενοι theatrizomenoi - you were made a public spectacle, as if in a theater; you were held up to public view, or exposed to public scorn. When this was done, or in precisely what manner, we are not told. It was not an uncommon thing, however, for the early Christians to be held up to reproach and scorn, and probably this refers to some time when it was done by rulers or magistrates. It was a common custom among the Greeks and Romans to lead criminals, before they were put to death, through the theater, and thus to expose them to the insults and reproaches of the multitude. See the proofs of this adduced by Kuinoel on this passage. The "language" here seems to have been taken from this custom, though there is no evidence that the Christians to whom Paul refers had been treated in this manner.

By reproaches - Repreached as being the followers of Jesus of Nazareth; probably as weak and fanatical.

And afflictions - Various "sufferings" inflicted on them. They were not merely reviled in words, but they were made to endure positive sufferings of various kinds.

And partly, while ye became companions of them that were so used - That is, even when they had not themselves been subjected to these trials, they had sympathized with those who were. They doubtless imparted to them of their property; sent to them relief, and identified themselves with them. It is not known to what particular occasion the apostle here refers. In the next verse he mentions one instance in which they had done this, in aiding him when he was a prisoner.

Hebrews 10:33 Parallel Commentaries

The Death of the Saviour the End of all Sacrifices.
(Good Friday.) TEXT: HEB. x. 8-12. DEEPLY as our feelings may be moved on a day such as this, deeply as our hearts may be affected with a sense of sin, and at the same time filled with thankfulness for the mercy from on high, that planned to save us by God not sparing His own Son, we can only be sure of having found the right and true use of the day, when we bring our thoughts and feelings to the test of Scripture. We find there a twofold treatment of the supremely important event which we commemorate …
Friedrich Schleiermacher—Selected Sermons of Schleiermacher

The Roman Conflagration and the Neronian Persecution.
"And I saw the woman drunken with the blood of the saints, and with the blood of the martyrs of Jesus. And when I saw her, I wondered with a great wonder."--Apoc. 17:6. Literature. I. Tacitus: Annales, 1. XV., c. 38-44. Suetonius: Nero, chs. 16 and 38 (very brief). Sulpicius Severus: Hist. Sacra, 1. II., c. 41. He gives to the Neronian persecution a more general character. II. Ernest Renan: L'Antechrist. Paris, deuxième ed., 1873. Chs. VI. VIII, pp. 123 sqq. Also his Hibbert Lectures, delivered …
Philip Schaff—History of the Christian Church, Volume I

Brought Nigh
W. R. Heb. x. 19 No more veil! God bids me enter By the new and living way-- Not in trembling hope I venture, Boldly I His call obey; There, with Him, my God, I meet God upon the mercy-seat! In the robes of spotless whiteness, With the Blood of priceless worth, He has gone into that brightness, Christ rejected from the earth-- Christ accepted there on high, And in Him do I draw nigh. Oh the welcome I have found there, God in all His love made known! Oh the glory that surrounds there Those accepted …
Frances Bevan—Hymns of Ter Steegen, Suso, and Others