Fringe Connections

Walter implanted a tracker in his neck in "Snakehead" which is used in "Grey Matters".

Jones is working with Bell, who is alive.

The hand glyph can be seen on a door in the pocket universe.

Olivia had a horse-riding ribbon in Nina's old photograph in "Novation". Nina rode horses herself in "The Cure" so it stands to reason that Olivia would have done so as well in the timeline where she was raised by Nina.

Observers send materials to themselves via shipping lanes from the future using metal cubes.

A flower can be seen outside the entrance to the daycare center.

Walter used the same neural halo in "Alone in the World" as he used on the Child in "Inner Child".

When Walter explains that his red/blue lensed glasses were created by his friend from Washington, Doctor Jacoby, he's referencing the television show 'Twin Peaks' which also had an eccentric man of science, Doctor Jacoby, who wore red/blue lensed glasses very similar to Walter's.

A seahorse pattern can be seen in the toxin's molecular structure.

Walternate has three solid-color panels on the wall of his office in "Bloodline": blue, red, and yellow. These symbolize the two universes (blue and red) and the rewritten timeline without Peter (yellow) starting from "Neither Here Nor There".

Marshall Bowman had a disk in his hand like John Scott and the woman in 'The Ghost Network'.

Butterflies can be seen in Olivia's bedroom.

The rollercoaster seen from atop the World Trade Center in Olivia's mind in "Lysergic Acid Diethylamide" is a reference to the one she rode with Ella in "August".

Mark Young's colleague is wearing a butterfly pin, possibly prompting the subject of his hallucination.

The leaf glyph is on the electronic keypad at Massive Dynamic.

Peter found Olivia in a field of white tulips in "Subject 13", a nod to "White Tulip".

The crane that crashed during the intro has a Massive Dynamic logo on it.

The butterfly glyph can be seen outside the entrance to the daycare center.

In "And Those We've Left Behind" Astrid used the same wand to detect abnormalities that Lincoln used in the opera house in "Over There (Part 1)".

The episode ends with September going into December's apartment, apartment 513, the episode code of the next and final episode of the series.

A seahorse can be seen in Walter's Monty Python trip.

In "Os" Peter revealed to Olivia that he was working on the Shapeshifter devices that he collected in "Reciprocity" by killing Shapeshifters.

The license plate on Olivia's SUV reads 1R2D21, and the licence plate on Broyles's SUV reads 1C3PO1.

A leaf can be seen on the bio-scan monitor at the Liberty Island security checkpoint.