Having gotten that big list out of the way (much bigger than I had expected), I'm going to have a look at the distinct "eras" of demon lords within the game. We'll call this first one "In the Beginning". Just prior to first edition AD&D, demons were introduced to the game, and they and their lords have remained a popular part of the game ever since. In this era, the most well known demon lords were introduced by Gary Gygax, and were seen by some as little more than just powerful monsters to be defeated, even though they were really closer to being on the same level as the gods. The main batch of demon lords were well described, and got plenty of playtime.
Orcus and Demogorgon were the first two demon lords in print, appearing first in Eldritch Wizardry (1976). The following year, they appeared in the brand-new Monster Manual, along with Juiblex and Yeenoghu. Lolth then appeared in the D-module series, Queen of the Demonweb Pits, and the Fiend Folio. In 1982, the roster of demon lords was expanded in the module The Lost Caverns of Tsojcanth to include Baphomet, Fraz-Urb'luu, Graz'zt, Kostchtchie, and Pazuzu, who were all reprinted the next year in Monster Manual II.
Also, the list on page 35 of the Monster Manual II included a few dozen demon lord names, most of which were not detailed until many years later. Zuggtmoy did appear soon after in the module Temple of Elemental Evil. Dagon and Obox-ob got mentions in the Demonomicon of Iggwilv series before getting detailed with statistics in FC1.
That said, the rest have yet to receive anywhere near as much detail in official canon D&D sources as those listed above, although that has slowly started to improve over the past decade.
Astaroth is mentioned as having been killed and replaced in the second edition Forgotten Realms book, Powers & Pantheons (1997) on page 22. Astaroth was further described in Dragon #357 (July 2007), in the article "Gazing Into the Abyss" on page 68, and played a role in the 2007 Savage Tide adventure path in Dungeon magazine #148 in the adventure "Wells of Darkness" on page 66.
Verin appeared in the Planescape supplement Faces of Evil: The Fiends (1997) on page 62 and was also detailed in FC1 on page 119.
Munkir and Nekir are depicted on the cover of Living Greyhawk Journal #3 (Feb 2001) battling the god Azor'alq at the gates of Heaven.
Gresil was briefly mentioned in the article "Artifacts of Oerth: Instruments of the Gods", a 2002 article which ran in both Living Greyhawk Journal #10, and Dragon #294 (April 2002) on page 97, where it was mentioned that his library has "millions of texts".
Socothbenoth was mentioned briefly in Fraz-Urb'luu's entry in "The Demonimicon of Iggwilv" series in Dragon #333 (July 2005) on page 29, and in Malcanthet's entry in Dragon #353 (March 2007) on page 27, and his realm was described in Dragon #358 in F. Wesley Schneider's article "The River Styx" (Aug 2007) on page 68.
Ardat was mentioned briefly in Baphomet's entry in "The Demonimicon of Iggwilv" series in Dragon #341 (March 2006) on page 24, and then received a full description in the "Demonomicon of Iggwilv: Apocrypha" edition in Dragon #359 (Sept 2007) on page 47.
Several of these demon lords also got some more details in FC1: Aldinach and Baltazo (p 115), Mastiphal (p 117), Asima (p 133; also in Demonomicon p 50), Areex (p 138), Cabiri (p 138, also Dragon #357 p 68-69), Azael (p 146), and Bechard (p 147).
Ansitif was detailed in FC1 on page 137. He was described as a vestige in Dragon #357 (July 2007), in the article "Gazing Into the Abyss" on page 67-68.
Soneillon was mentioned in the web enhancement for FC1:
Fiendish Codex I: The Lost Entries
Ahazu played a role in the 2007 Savage Tide adventure path in Dungeon magazine #143 in the adventure "Tides of Dread" (Feb 2007), and he played a significant role in #148 in the adventure "Wells of Darkness" (July 2007).
Abraxas, Ahrimanes, Alrunes, Anarazel, Azazel, Barbu, Bayemon, Charun, Eblis, Laraie, and Nocticula have yet to receive much coverage beyond the index in the back of FC1 aside from trivial name drops. Bayemon was mentioned in FC1 as having been one of the few beings to escape from the Wells of Darkness.
Aseroth and his realm of Soulfreeze were described in Demonomicon (2010) on page 78.