Some slots have items with higher agility.
Back : green
[Amber Cape] of of Agility, 32 agi
Twohander
[Deepforge Broadaxe] of Agility, 56 Agi
Ring
[Amber Band] of Agility, 32 agi
Trinket :
[Alchemist's Stone], 15 agi
Hard to count metagem in tier6 because we fill all gemslots with red only.
Good endgame survival ranged is
[Legionkiller] with 21 agi.
For belt, being survival hunter I still have not decided between
[Belt of Deep Shadow] and
[Belt of the Black Eagle] (17+20).