About unique items in D2R
Uniques are the gold-named items with fixed (but variable-rolled) stats. Every unique is tied to a specific base item — the Harlequin Crest is always a Shako — and comes in one of three tiers: normal, exceptional or elite. Higher tiers mean better base damage or defense, but also higher stat requirements. Many normal and exceptional uniques stay relevant into the endgame because their modifiers do the heavy lifting, not their base numbers.
When a stat shows a range, the item rolls a random value in that range when it drops. Stats marked "Based on Character Level" scale as your character levels up, reaching the listed maximum at level 99. Normal and exceptional uniques can be upgraded to the next tier with Horadric Cube recipes — the base changes, the modifiers stay — which is how classics like Goldwrap and the Titan's Revenge keep up in hell difficulty.
Notable uniques worth knowing
The most-wanted drops every ladder: Harlequin Crest (Shako), The Stone of Jordan, Arachnid Mesh, War Traveler, Mara's Kaleidoscope, Griffon's Eye, Crown of Ages and the class staples like Titan's Revenge, Arreat's Face and Death's Web. The Annihilus and Hellfire Torch charms come from the Uber events rather than regular drops, and Gheed's Fortune is the only grand charm with magic find. Reign of the Warlock added new jewelry, grimoire uniques and craftable sunder charms — all included above.