Craft grey dye by combining 1 black dye and 1 white dye in the crafting grid
Craft black dye from ink sacs, wither roses, or by smelting certain items depending on the source
Craft white dye from bone meal or lily of the valley
Find grey dye as a trade from some wandering traders
Use grey dye on wool, glass, terracotta, beds, banners, candles, shulker boxes, and other dyeable items