Didnt even know this was a thing added until a reddit post...
Luck is a hidden statistic that influences the random nature of various activities in Terraria. There are various ways to increase and decrease this statistic, such as buff potions and Torch placement. Players can estimate their luck value by speaking to the Wizard. Luck influences many of...
terraria.gamepedia.com
annoying hidden and huge potential effect of Luck...
1.Torches effect luck. +.2 luck, when within 42 tiles of a torch MATCHING the biome you are in. -.4 luck if within 42 tiles of a NON-matching biome.
(so carry and use jungle torches in the jungle.)
More arena stuff.
Sunflowers from the dryad give a move speed buff as well.
so, sunflowers(must be placed on grass or hallow), campfires, heart lanterns, star lanterns, honey pools.
Potions.
you mentioned iron skin.. but to be clear..
regen, restoration potion, endurance potion, lifeforce potion, rage potion, wrath potion.
archery, mana regen/magic power, summoning potion..
Theres a bunch of potions from fishing, you didnt mention...
(I dont think you can make flasks yet?)
I don't remember the specific progression for the destroyer. Daedalus Stormbow, I do remember being super op, and I think especially vs him.
if you find you are dying too easy. can also reroll all your equipment for "warding" and +4 defense on each of them.