Most ironically useless items...

[ShadowHM]

"Mechanic's", "Artisan's", and "Jeweller's". They do what was already done, what can be added upon via quest reward or recipe, and only serve to dilute out the affix pool.

I actually like and use a number of armour items with those prefixes. I tend to save my Larzuk quest rewards for use in Hell mode, when I finally find an item that is worthy of squandering my socket quest on. In the interim, for example, I have a character wearing a three socketed (Ral, Ort, Ort) armour of the Squid. My Act 2 mercenaries often wear three or four socket armour of Stability or Swords. A rogue mercenary can go far with a plain Jewellers armour.

It may dilute the affix pool in one way, but it makes decent resists available for many lower level or item poor characters.