Enigma was fantastic, it sped up all that monotonous Baal running and grinding tremendously for non-sorc classes and was what gave a number of builds their viability in the first place, particularly PvP-wise.
Wind Druids, BvC's, Necros in general and Ghostsins for starters.
HDins already function remarkably well with just desynch backing their Hammer spam (though tele blitzkrieging thanks to nigma is of course nice to have), Sorcs have innate tele already, and Zons are strutting around in Forts + high MS gear and GA'ing people from off-screen.
Good luck catching / killing any of these if you're one of the other classes and not sporting Enigma.
Regardless, almost every slot had only a few top tier items that were overused to begin with, usually one at Enigma-level popularity or close to it and some other alternatives (e.g. Fort and CoH).
Nearly every single class with exception given to Barbs could make excellent use of Spirit, 35/80 STarge Spirits were top tier for HDins, whilst regular 35 FCR iterations were used by everything from Sorcs, Wind Druids, Necs, Sins, you name it. Stormshield was also ridiculously popular for good reason and Smiters either ran Exile or HoZ.
HotO was a predominant caster weapon of choice, Wizzy for res stack. Of course 174 FCR Wind Druids often used SBranches socketed with life gems, whilst Sorcs had Fathom / Eschutas as a HotO alternative.
GriefZ and EBotDZ were king for melee-based toons, Smiters, BvC's, Wolf Druids, whatever, Lib HDins could run either.
Gloves? Trangs for casters, Dracs for melee.
Maras or gfg rare for the ammy slot. Cats-eye for Zons.
Rings-wise, everyone and their mothers ran at least one Ravenfrost, other slot was filled by a gfg rare. Poorer players of course substituted the second slot for an SoJ or BK.
Bottom line? There were only really a select few items for each slot that ever saw great popularity at the highest tiers of playing in D2, with exception given to niche builds like Auradins sporting HoJ and dual Dragons, or people using goofy setups, e.g. DoomZ on a Wind Druid. Enigma is certainly not the only culprit to be pointing fingers at in terms of how the meta was overcentralised.