Melee: Night’s Edge
Ranged: Demon Scythe and Space Gun
Armor: Molten (Meteor, if using space gun)
Potions: Health, Restoration, Ironskin, Thorns, Shine, Obsidian Skin/Water Walking (in case you fall in lava)
It can also be a good idea to have a summon (Slime Staff, Imp Staff, Hornet Staff)
Make sure you have camp fires, heart/star statues, and heart lanterns set up in your arena to help you regenerate mana and health faster.
Hope this helps, and good luck beating WoF!