Tales of the Jedi is one of the biggest tie-ins to the Expanded Universe. The Dark Horse Comics story was later subtitled ‘Tales of the Jedi: Knights of the Old Republic’ and was followed three sequels arcs: Dark Lords of the Sith, The Sith War and Redemption. It also had a prequel, Golden Age of the Sith and the Fall of the Sith Empire. It would be very difficult to overstate it’s influence.
The first Dark Horse comic released was Dark Empire, which mentions in the narrative the events that will be told in the Tales of the Jedi series. Tales of the Jedi is one of my favorite reads, you can read my review here.
But lets start in chronological (in universe) order: (warning: here there be spoilers!)

We have Golden Age of the Sith and Fall of the Sith Empire which tell how Naga Sadow attacks the Ancient Old Republic on when they are discovered by a pair of desperate Hyperspace Explorers, Gav and Jori Daragon. He is resisted by Empress Teta of the Koros system and the Jedi Knights.
Tales of the Jedi Golden Age of the Sith and Fall of the Sith Empire Introduced:
- Sith Lord Marka Ragnos
- Sith Lord Naga Sadow
- Sith Lord Ludo Kressh
- Empress Teta and Koros system AKA Tetan System
- Odan Urr, Jedi
- Celegians (species)
- Sith Species
- Massassi as a sub species.
- Korriban – planet (first in universe reference)
- Ziost – planet
- Solar Sailor starships
Tales of the Jedi: Knights of the Old Republic – Redemption eras Introduced:
- Jedi Uliq Qel Droma
- Jedi Cay Qel Droma
- Jedi Tott Doneeta
- Jedi Master Arca
- Jedi Oss Willum
- Jedi Nomi Sunrider
- Jedi Vima Sunrider
- Jedi Master Thon
- Jedi Sylvar
- Jedi Crado
- Jedi Vodo Sioskk Bas
- Jedi Ood Bnar
- Dace Diath
- Jedi / Sith Exar Kun
- Alema and Satal Keto, heirs to Teta and Sith followers
- Freedon Nadd (Sith spirit)
- Planet Onderon and moon Dxun, City of Iziz,
- Ambria – dark side world
- Ossus – Jedi library
- beast riders
- Mandalore culture
- Rhen Var
- Miralukans (species)
- Cathar (species)

Tales of the Jedi: Knights of the Old Republic introduces Uliq Qel Droma, his brother Cay, Tott Doneeta, Arca, the planet of Onderon and it’s moon of Dxun, the city of Iziz, Freedon Nadd and their conflict. It’s other part entails Nomi Sunrider losing her husband and with her daughter Vima, traveling to be trained by Master Thon as a Jedi.
Tales of the Jedi: Freedon Nadd Uprising. In this the victory against Freedon Nadd supporters of Iziz gets set back by their retaliation. Ultimately though the remains are entombed on Dxun.
Tales of the Jedi: Dark Lords of the Sith: Heir to Empress Teta are now dabbling in the Dark Side and pay a visit to Iziz, gaining Sith knowledge just before its locked down. Meanwhile Exar Kun, is resisting his Jedi Master’s teachings and goes hunting knowledge there. The Tetan heirs wage war on the Republic, with Uliq receiving an unhealing Dark side infused wound and many Jedi falling in a sneak attack. Meanwhile Kun follows what he finds in Freedon Nadd’s tomb to Korriban (first mention of the Sith homeworld), then Yavin 4 and finally becomes a full Sith Lord. Uliq’s attempts to conquer the Dark Side from within by pretending to join Alema and Satal, the Tetan heirs, ends in his fall to the Dark side. Jedi Cathar Sylvar, Crado are introduced as well as Vodo Siosk Baas.
Tales of the Jedi: The Sith War: How Exar Kun led so many Jedi to the Dark Side is told here, the fall of the great Jedi world of Ossus, Uliq’s conquering of the Mandalore and winning their allegiance and how he finally turned away from the Dark side and Exar Kun was stopped are here. Ood Bnar makes an appearance. Odan Urr dies.
Tales of the Jedi: Redemption: How Vima Sunrider seeks out Uliq to train her, as he is hiding on Rhen Var trying to forget his past and be forgotten. Sylvar also is at a crossroads, filled with rage over the loss of her mate in the war.
Fall out
KOTOR’s Jolee Bindo, as well as a short Tales story suggest that their were a number of Jedi with emotional attachments that fell to the Dark Side in the Sith War.
By the Mandalorean Wars we see the first Jedi being trained as children, though no sign that they are denied family contact.
By SWTOR, marriage and family relationships are highly discouraged, as evidenced by Satele Shan giving up Theron to her Jedi Master to raise in secret. There is a story quest on Tython where one can choose to encourage or discourage a relationship between 2 padawans. The Hero of Tython (if playing a male) can choose to romance Kira Carson, his fellow Jedi. But if so they have to keep it secret.
The Sith teachings of these ancient eras will be discovered and studied by Darth Bane. Lessons learned here (as well as from Revan’s holocron) will form the basis for his destruction of the Brotherhood of the Sith and the foundation of the rule of Two, which ends at Darth Sidious and Vader.
Stories Influenced
The Movies
Attack of the Clones: Dooku’s solar sailer is similar to the ones in Tales of the Jedi: Golden Age of the Sith.
Darth Maul’s lightsaber is based on Exar Kun’s.
Comics

Shadows and Light: Dark Horse Comics Tales. This is one of the few stories in Tales that fits with EU canon. Duron Qel Droma is related to Uliq and Cay. His quest for the left over monsters of the Sith War and his love for a fellow Jedi are the basis of the story.

Knights of the Old Republic by John Jackson Miller, the Dark Horse comic book series inspired by the games, follows the adventures of Jedi Padawan from Taris, Zayne Carrik. He is framed for murder. Among these adventures he encounters weapons and items left over from the great Sith War, such as Exar Kun’s lightsaber. Part of his troubles arise from a Jedi Covenant which arose specifically to prevent the return of the Sith, by those traumatized by Exar Kun and his followers.

Jedi VS Sith by Darko Macan is features the battle of Ruusan. Darth Bane is in it and he visits Ambria. This depicts the same events as in Darth Bane: Path of Destruction from a different point of view.

In Republic Comics, Dace Diath and his father, Jedi Sidrona Diath is mentioned. Dace fights in the Sith War. His father is mentioned in the Tales of the Jedi Sourcebook. During the Clone Wars, we meet three Jedi with ties to this era. Nico and Tae Diath, are Master and Padawan. Nico is Tae’s Uncle. These are descendants of the same bloodline.

Dark Empire, Dark Empire 2, Empire’s End: When Leia Organa Solo steals a holocron from the clone emperor, it warns her that those who try and defeat the Dark side from within ways fall. It tells the tale of Uliq. Also Vima Da Boda is said to be descendant of Vima Sunrider. They also end up visiting Iziz.
This story actually introduced the Tales of the Jedi. It came first in publishing.
The Games

Knights of the Old Republic Lucasarts game
The Mandalorean war with the Republic was ended by Jedi heroes Revan and Malek. But they went against the Jedi Council to do it and have now returned as Dark Lords of the Sith. As the player pieces together the secrets of his lost past, the mission to find Malek includes meeting Jolee Bindo who talks about the Great Sith War. Initially Vima Sunrider was to be a part of this, but was changed to Bastila Shan due to trademark issues with the name Sunrider. In game discoveries include gear that belonged to the heroes. Worlds visited include Taris (first intro) and Korriban where you explore the Tales of the Jedi Sith Lord’s tombs.

Knights of the Old Republic 2 the game
The Exile was a Jedi who served as general alongside Revan and Malek. She returned to face the Council judgement and did not join the Sith. However she loses her powers and in her quest to regain them finds someone has been stalking and killing the Jedi. The fallout of what became known as the Jedi Civil War (Malek and Revan vs the Jedi) has left the galaxy untrusting of the Jedi. Among the missions here one visits Dxun and Onderon, where the Great City of Iziz still thrives with comparative peace between beast riders and the city inhabitants. The Queen is Talia, descendent of Galia who helped the Jedi overthrow her parents, who worshipped Freedon Nadd. Telos, a world badly damaged in the war, and even Korriban itself are other locations.

Star Wars The Old Republic the game
Places like Carrick Station and fleet ships names tend to be nods to other eras. Korriban and Ziost is a playable world on the visit list. Nomi and Arca of Tales of the Jedi are among the Noetikon Masters.You visit the tombs of Naga Sadow. Many datacrons are full of info straight out of the Tales of the Jedi comics and the server names too, refer to other stories.
Recently Ossus, Onderon and Dxun from Tales of the Jedi were added into the game’s planets. The first two are fully playable, the moon of Dxun is only accessible via a group Operation raid.

Clone Wars (2002 game) Among the missions to stop the Separatists and Dooku, one finds he is on Raxus Prime looking for components of the Dark Reaper and Force Harvester, a weapon that harvests the Force. The trail leads to Rhen Var and the spirit of Uliq Qel Droma, who instructs Anakin in how to defeat the machine without being consumed by it.

Jedi Academy the game: Jaden Korr, apprentice to Kyle Katarn, helps track down the disciples of ancient Sith Marka Ragnos from Golden Age of the Sith. They are using similar technology to the Force Harvester but on a much smaller scale.
Books
Crosscurrent by Paul Kemp begins during Naga Sadow’s attack. The Sith ship called the Harbinger, due to Jedi sabotage, has a hyperspace mishap that lands them in the New Jedi Order era. The ship was to meet Naga Sadow’s forces.
Lost Tribe of the Sith by John Jackson Miller is involved in the same events as Crosscurrent. The Sith ship Omen, collides with Harbinger as they are heading for Hyperspace and crash lands on Kesh. The descendents remain there until the New Jedi Order era. Ludo Kressh was one of the mentioned Sith Lords, the ship was to meet with Naga Sadow’s forces.
Star Wars The Old Republic: Annihilation by Drew Karpyshyn has SIS agent Theron Shan (who also appears in game) visit Ziost to steal a black cipher.
Darth Bane: Path of Destruction, Rule of Two, and Dynasty of Evil all have visits to Ambria, home base of Jedi Master Thon in Tales of the Jedi.

Jedi Academy trilogy by Kevin J. Anderson: Luke Skywalker opens a Jedi training academy on Yavin 4, awakening the trapped spirit of the Sith Exar Kun. The students unite to defeat him.

Junior Jedi Knights: The Golden Globe: by Nancy Richardson Young Anakin Solo and his friend Tahiri find a powerful Sith artifact containing the spirits of Massassi children, held prisoner since the time of Exar Kun.

Young Jedi Knights: Lightsabers by Kevin J. Anderson & Rebecca Moesta, A traumatic lightsaber accident causes Jaina and Jacen Solo with their friends to doubt their abilities. Jedi historian Tionne gives them a lesson of Nomi Sunrider’s struggles with the same issue.
Legacy of the Force: Exile by Aaron Allston and Sacrifice by Karen Traviss has Ben Skywalker visit Ziost on a mission.