The Melancholy of Haruhi Suzumiya (TV 2009 renewal)

In the "Endless Eight" arc, the costumes that Kyon, Mikuru, Yuki, and Itsuki wears are the same type as in Lucky Star OVA with Kyon to Kagami, Mikuru to Tsukasa, Yuki to Miyuki, and Itsuki to Konata.

In the episode Bamboo Leaf Rhapsody, the book that Nagato is reading shortly before she leaves the clubroom is "Time Enough for Love" (愛に時間を - Ai ni Jikan wo).

In the episode "The sigh of Haruhi Suzumiya #2" (the 21st in the global list), at around 11'20", the melody Haruhi noisily hums is the famous "cancan-like" music from Jacques Offenbach's famous opera called "Orpheus in the Underworld".

In the episode "The sigh of Haruhi Suzumiya #1" or 20th chronological, at around 20:04. On the train Kyon is standing net to two girls who look quite similar to the characters Yui and Mio from K-ON!. The change in character designs for season two is also similar to what was used in K-ON!.

The "Mio and Yui cameo" characters are wearing uniforms that look pretty much like the Kouyouen Academy school uniforms, a possible foreshadowing of the Vanishment arc.

About 1:50 into The Sigh of Haruhi Suzumiya Part 5, the song Haruhi is humming is "Ride Of The Valkyries" by Richard Wagner.

In the episode "Endless Eight"or 15th chronological order, at around 11:59. Kyon said about how it feels for Virtue to do a purge. This is a reference from Gundam 00 series in which a gundam named Virtue purges its armor to transform into Nadleeh form.

In the episode "Endless Eight" Loop 15,524 (ep. 17) at around 12:30 Kyon makes a final reference to the Gundam franchise in the "Endless Eight" arc. This time Kyon refers to a mobile armor from the original Gundam series, Mobile Suit Gundam, known as the MAX-03 Adzam. He even goes so far as to refer to its titular weapon known as a "leader" which is designed to trap enemy units and destroy them via super-heated particles.

Contains all 14 episodes of the original series mixed in with 14 new episodes, all rearranged into chronological order.

In the episode "Endless Eight" Loop 15,521 (ep. 16) at around 11:00 Kyon makes an additional reference to "Neon Genesis Evangelion". In particular, it references a scene in episode 6 in which Evangelion Unit 00 shields Evangelion Unit 01 from a particle beam launched by the diamond-like Angel Ramiel. As a result of the attack, Unit 00 sustains "severe thermal damage", or damage caused by high levels of heat. As such, working in a frog suit in the sun for a few hours and comparing the experience (humorously) to Ramiel attacking Unit 00 with a beam makes sense.

In episode 13 till episode 19 (the "Endless Eight" episodes) whenever Kyon is at his desk trying to do his homework, the poster in front of him is featuring former F1 race driver Ayrton Senna while he was driving for Lotus. Strangely, in the very first eps of "Endless Eight", there is a different poster showed.

In episode 19(S2) or the last story arc of the “Endless Eight” saga, everyone is wearing the same exact swimwear in the pool as they did on the beach in the Remote Island Syndrome (Part 1)(S1) episode, if you did notice or not.