Book of Impracticality - 15K
Greaves of Obscurity - 7492
Ring of Dark Intellect - 15755
Earring of Thunder - 11175
Tear of the Rainmaker - 18731
Ring of Absurdity - 4560
Chetari Wardstaff - 2400
Kylong Shinguards - 8100
You'll notice some of those are from GE nameds. It is not uncommon for me track nameds in there for a couple hours and come home with +30k in tribute and about 2k in plat/vendor loot.
and what is the best tribute item that stacks ?
What do you mean by this? Tribute effects? If so, I use Fero, Vengeance, Heal focus, and DoT focus. I was also using tribute for mana regen, but cancelled it since getting my 2nd Runelinked Bracer. (+5 mana regen on each). Tribute effects are counted as 'worn' buffs and, as such, stack with any traditional buffs that go to your buffbar.
I would think that most people just use whatever they feel they need the most from trib: tanks usually get HP, STA, AC, and regen; casters usually get mana, mana regen, INT or WIS, and some foci; hybrids can use all the tribute they can get their hands on, which is quite often a mix of casting and melee enhancements. It all depends on your own toon's progress, and where you think you will be fighting next.