It depends on the item and what the rolls are. The most commonly rolled are Caster Amulets.
For those you want:
+2 Skills, particularly valuable are:
Sorceress, Lightning (Sorc), Cold (Sorc), Fire (Sorc), Druid, Elemental (Druid), Paladin, Combat Skills (Paladin), Barbarian, Warcries (Barb), Necromancer, Bone and Poison (Necro).
Faster Cast: Looking to get 20% (especially for Barbarian or Sorceress), but some can be quite valuable even lower depending on Breakpoints. Faster is always better, but a few that are still decent are 18% or 15% combined with Paladin or Necro skills, 18% combined with Druid skills is almost as good as 20%.
That leaves 2 additional mods that can roll, and it’s more flexible there, but some of the best stats are All Resistances (up to +20%), + Strength (up to 30), + Mana (up to +110), and +Life (up to +60). Teleport charges can be useful early Ladder.
Other valuable crafted items include:
Safety Amulet: You want + Skills, +10% Increased Block Chance, and other valuable amulet stats (see Caster Amulet above for details). Mainly PvP players looking for this, so might take time to find a buyer.
Blood Gloves: You want +2 skills (Bow and Crossbow, Javelin and Spear, or Martial Arts); 20% Increased Attack Speed; and other useful mods (probably Resistances and Dex/Strength).
Blood Belt: You want good mods, meaning Resistances (especially Fire or Lightning); + Strength, +Life, or Faster Hit Recovery (up to 24%).
Hitpower Gloves: You want +2 Bow and Crossbow; 20% Increased Attack Speed; and other useful mods.
Hitpower Scepter: If you roll the Fools Mod (damage and AR based on Character level) in combination with +2 Paladin Skills, 40% Increased Attack Speed, and the staff mods +3 Zeal, and +3 Holy Fire/Freeze/Shock you will have an extremely valuable weapon for an elemental Zealot. It’s a niche build however so it might take time to find a buyer willing to pay full price. Similarly, a Hitpower Caduceus can roll up to +510% Enhanced Damage, if you get something like that along with +2 Paladin Skills, 40% IAS, and +3 Zeal, +3 Fanaticism you have a great weapon for a physical zealot (not as niche so easier to find a buyer for).
Caster Scepter: Similarly, a Caster weapon can be rolled on Scepter that could be potentially BIS for a Fist of the Heavens Paladin. You’d want +2 Paladin Skills (Combat Skills will also work), 10% Faster Cast, and +3 Fist of the Heavens. Also, a pretty valuable weapon for a Hammerdin if you get +3 Blessed Hammer and +3 Concentration, (not quite BIS, though equal or better than HofO).
Caster Wand: You want +2 Necromancer Skills, 20% Faster Cast Rate, 2 sockets, +3 Poison Nova, +3 Lower Resist. That gives you a wand that is best until you can find a Death’s Web.
Caster Belt: The higher Faster Cast the better, along with useful mods (probably Resistances especially Lightning and Fire, + Strength, or +Life).
Safety Shield: You want 10% Magic Resistance, 20% Increased Chance of Blocking and 30% Faster Block Rate, with All Resistances +20%, as well as two other good mods. Again this is for PvP so might take time to find a buyer.
I have a comprehensive post on Crafting and ideas for changes to make more of the recipes valuable.