The first replies actually has surprisingly comprehensive list of early pioneers. Those producers pretty much made the building blocks of what trance became. Eye Q and Platipus as labels had a colossal impact to the scene.
But I guess we need to look things further. A shortlist of sorts here.
I am not so sure about the 95-99 to be honest. I guess it was about taking gradual steps towards more commercial sounds with what was called "progressive" back then. One could argue Robert Miles had a lot to do with the commercialization of the trance sound even if Dream Trance was also labelled Dream House. Hard to argue against the importance of Children though. Or from different artists BBE's Seven Days And One Week.
From the progressive trance/house/whatever, we slowly got the first superstar DJ's. Sasha, John Digweed and Paul Oakenfold are probably the easiest names to mention resulting the peak of Global Underground around 99. Pretty much everyone who has listened to trance longer time knows Xpander or Heaven Scent.
Few other random mentions from the era, Chicane (Far from the Maddening Crowds album as well as hugely popular Offshore, later Behind The Sun with Saltwater/Don't Give Up). BT pushed the technology and sounds a lot releasing few respected albums with big some big hits (Flaming June especially). Three Drives - Greece 2000 has also stood the test of time.
Eventually around 1999 we got into the uplifting trance, especially driven forward by the Dutch. Ferry Corsten is by far the biggest name of the era, but there are a lot of others too like the already mentioned Vincent De Moor. Of course it wasn't just the Dutch as the era spawned big hits made by for an example Push (Universal Nation) or Matt Darey (own tracks, Lost Tribe - Gamemaster etc.).
Laurent Véronnez best known as Airwave has been hugely popular and versatile during his career with like tens of different aliases.
In the 00's we moved to an era where we got big superstar trance DJ's topping DJ Mag's DJ list year after year. Ferry Corsten and Paul van Dyk were among these, but one cannot go without mention of Tiësto having many big mix compilation series as well as hugely popular own tracks. Armin van Buuren eventually became popular with A State Of Trance radioshow. And some kind of a change in uplifting sound was also made by Above & Beyond and the Anjunabeats label.
The list could go on and on, but I leave filling the gaps to the others. This was pretty much from the top of my head anyway.