Minecraft wiki entry for Starting_in_the_Nether, associated text: Dirt. Grows just about everything else.
A few saplings. Wood can be smelted for charcoal.
Sugar cane. Can't grow it in the nether. And an elytra?
Cactus. Makes a really good AFK magma cube farm with hoppers.
Bamboo. For scaffolding.
Carrots and melons. For potions.
Ice. Basalt generator.
Two Wolves. Alternative to trident killers.
Stone (for grindstone, stone cutter, blast furnace, and armor stand)
Sand (for glass and TNT).
Turtle eggs. For the gold farm.