Buy For Gold, Sell For FSP

A list of items that are possible to convert into FSP, arranged by the general difficulty to sell:

Easy

Eribor items
Buy For - ~5K gold
Sell for - 1 FSP, 2 FSP for gloves

Tassodans Rune
Buy For - 1K/2K gold
Sell For - 1 FSP

Spearing Rune
Buy For - <3k gold
Sell For - 1 FSP

Blood Demon items
Buy For - Sword or Boots <5K, Helm <10K, Armour 5-10K
Sell For - Sword 1 FSP, Boots 1-2 FSP, Helm 2FSP, Armour 1-2 FSP

Glowing Gloves
Buy For - <8k gold
Sell For - 1/2 FSP

Golden Visor
Buy For - <7k gold
Sell For - 1 FSP

Ring Of Fire
Buy For - 5K gold
Sell For - 1 FSP

Medium

Striking Rune
Buy For - <1K gold
Sell For - 1 FSP

Rune Of Constitution
Buy For - <1K gold
Sell For - 1 FSP

Frostbite Shield
Buy For - <1K gold
Sell For - 1FSP

Nomad Items
Buy For - Neckpiece <700 gold, Scimitar <1.5K gold, Shield <2K
Sell For - 1 FSP all items

Hard

Mystical Hood
Buy For - <1K gold
Sell For - 1 FSP

Infernus Helm
Buy For - <1k gold
Sell For - 1 FSP

Chilling Plumed Helm
Buy For - <1K gold
Sell For - 1 FSP

Amulet of Pain
Buy For - <10K gold
Sell For - 1/2 FSP
More to come....

This does work really well, done it many times, and while you are scouting for these bargains keep one eye open for HellForged items. It does not happen a lot but some times you find them in auction for a silly price (found an AssasinsHat, Fully Forged for 100 gold), once in your backpack you can unforge them and rake in the FSP's some poor sod spent on it, but I guess this will change after the restyling of the HellForge system that is underway.