Russia(bolstered by some Ukrainians who for various reasons opted to play for them) had a crop of very good midfielders back then, that were mainly the product of ussr youth development system before the youth production line had dried up later. I'm guessing most would be obscure now (and a lot even then unless you were a hardcore fan of la liga or international football) considering the clubs other than the occasional semi-final, quarter-final and second group stage run weren't strong enough overall to do much consistently and the NT was an underachieving, mostly poorly managed mess that often had enough drama and cliques in the squad to make the Dutch or Argentines look thoroughly unified. Some players are worth checking out as individuals though.
Ilya Tsymbalar - left-wing and attacking midfielder for Spartak. Very talented Ukrainian player with glass knees, his peak was short 93-96, only had about one season worth of football after that where he wasn't mostly injured. He was an excellent passer with an effortless, smooth playing style that when fit enough always played very well in the big european and NT games. Had offers from Lazio and Inter Milan after Euro 96 but the injuries ruined that.
Aleksander Mostovoi - centre and attacking midfield for Celta Vigo from mid-90s. One of the biggest young talents of last years of ussr league. A great technician and orchestrator, but with a very difficult character(basically a huge arsehole) he wasted most of the first half of his career abroad then turned things around at Celta where he really elevated a club close to relegation when he arrived. Played at a world class level for years there, but must be getting forgotten about nowadays if fans are voting the significantly less talented Iago Aspas a better player for the club. Liked to be the big fish in small pond though and turned down a move to Juventus after putting them out of the uefa cup. Rarely seemed to care about the NT, only 50 caps in 10-12 years of being favoured.
Valery Karpin - right-wing and centre midfield for Valencia, Celta and Sociedad. Unlike a number of the more talented teammates from that era that often had issues with professionalism, he was a stamina laden gym-rat that was extremely competitive in a Nedved'esque all action way, and also brought an excellent technique. I never liked the guy as he was also a huge arsehole and windup merchant on the pitch, but he has to be one of the most underrated, rarely mentioned excellent players of that era. I thought only Figo was consistently better than him in la liga from the wide mid positions, some of the younger up and coming Spanish wingers like Vicente and Joaquin got more hype and were faster, flashier dribblers, but they didn't have his box to box qualities, passing/crossing technique or vision. His decision to move on after one season at Valencia and team up with his former spartak and NT teammate at Celta was a poor choice for his own career in retrospect. He did have a late surprising offer from rival Deportivo, but their fans hated him so much i believe they staged a protest to get it cancelled
Egor Titov - centre and attacking midfield for Spartak. He was the big hyped player in the Russian league from 97-03, overhyped really as he was quickly compared with Netto and Voronin and after good European and NT performances the Zidane comparisons started from spartak biased media sources( being a tall, elegant attacking mid this was probably inevitable from the more hype susceptible late 90s hacks). Overhyping aside, he did seem to have the goods to be an excellent player at a higher level...impeccable two-footed technique, flair, great eye for a pass, high workrate, very strong and had a number of high quality performances against really good midfields like Ajax, Real with Seedorf and Redondo, Leverkusen, 4-1 vs Arsenal, French NT, Inter Milan and others. However he didn't follow them up with a move abroad despite offers from Bayern and Atletico, opting to stay loyal to a rapidly declining Spartak and then largely killed his career by failing a doping test before Euro 2004. Likely hated in Wales until they got their revenge at the last Euro.
Dmitriy Alenichev - Centre midfield for Spartak, Roma and Porto. A fine supporting playmaker with very good passing and dribbling, though he was physically weak midget and mainly suited to a multiple-playmaker, short passing focused way of play, which was Spartak's long held traditional style. He predictably failed at Capello's Roma, not having the defensive qualities for fabio's workhorse midfield setup at all, then did well at Porto where he eventually won everything with Mourinho. Always very good with the NT.
Andrey Tikhonov - Right and Left wing for Spartak. Probably the most well loved player across club boundaries in Russian football past few decades, though wasn't considered by many to be the individual talent his teammates Tsymbalar and Titov were, i still found him to be a very good player with a smart, effective style and fine skills that was wasted playing in the Russian league. He was far too loyal to Spartak though, but ended up stabbed in the back for it when increasingly erratic, alcohol fuelled manager Oleg Romantsev started a feud with him and kicked him out of the club in 2000 despite having another 2 or 3 seasons in him. Never played much for the NT due to Karpin\Kanchelskis on the right and Tsymbalar on the left, then getting shafted by Romantsev who was well into the process of running Spartak and any last chance that generation had at a solid international level showing into the ground.
Dmitriy Loskov - Centre and attacking midfield for Lokomotiv Moscow. Two-footed passing virtuoso that while never fast, had a great vision of the field and reliable big game player, loads of goals and free kicks. Also shafted by Romantsev, fair enough if he favoured Mostovoi and Titov over him, it was arguable but he should have been in NT squads far earlier than he did. Has a good argument for being the greatest midfielder in the league history so far, should be no lower than top 3 imo. Made "fifth wheel" Lokomotiv the main challenger to Spartak and eventually broke their dominance with their first ever league titles and orchestrated various fine performances in Europe, especially against Real Madrid and Inter. I remember 2003/04 R16 vs Monaco when Morientes got him sent off 20 minutes into the 2nd leg with Loko 2-1 up and looking good. That turned the momentum around and they got an away goals win...making the quarter final would have been a fantastic achievement for a club of Loko's size. Watching him in the russian league in his prime was like watching Hagi or Alex de Souza in Turkey, you knew they should be challenging themselves at a higher level, though i don't think Loskov ever had any interest to leave. He was very loyal to Loko and a very laid back guy lacking in ambition.