This is to go with plugin LootCrates
For locked chest (Can get locks from buying and voting) will be rare lucky votes
Default items +
Diamond set all p1 (chance to only get one piece per chest)
Diamond Tools with both unbreaking 1 and efficiceny 1
2 golden apples
1 God apple
32 tnt
32 obsidian
bow with power 3
diamond pickaxe with unbreaking 3
diamond pickaxe with efficiency 3
For unlocked chest
Default items +
8 tnt
Full iron set w/ p2
diamond sword
diamond pick
8 bread
32 arrows
16 obsidian
full iron tools
16 steak

(If the Plugin LootCrates will not cooperate, just throw everything listed, into another plugin)
If you do have to use another plugin, here are the default items of LootCrates
Locked
5 diamonds
2 diamond blocks
1 silk touch diamond pick
1 knockback diamond sword
unlocked
apple
1 diamond