Some of the stories that are after the events of Halo 3 are Halo 4 (duh), the Kilo-5 books, Initiation, Escalation, The Return, Spartan Assault, and the upcoming Halo 5 and its digital series Nightfall (again, duh) but is there anymore stories or did I pretty much just list everything there is to know?
I just want to make sure if I missed anything or not.
You could technically throw in bits of Halo: Primordium that are set in the post-Halo 3 setting with the UNSC Rubicon and the interrogation of Guilty Spark/Chakas and Silentium’s beginning talking about how they got the info presented in the book via recovered datastreams. But those are technicalities.
The Petra short story in the Defintive Edition of First Strike and From the Office of Dr. William Arthur Iqbal in Evolutions also count. Maybe you could used The Impossible Life and the Possible Death of Preston J. Cole as well if you want to stretch it a bit since the story is set as a report made after the war.
Alright, well, I guess that sums it up.
Well everythings pretty much been mentioned but heres a full list of post war content, Include the final cutscenes from Halo 3
Main stuff
Halo 3 Voi memorial cutscene
Halo Evolutions The impossible life and the possible death of Preston J. Cole
Halo Evolutions From the Office of Dr. William Arthur Iqbal
Halo Evolutions The Return
First Strike Adjunct Section Tug O’ War
First Strike Adjunct Section Petra
Grasslands
The Thursday War
Mortal Dictata
Halo Spartan Assualt
Halo Initiation
Halo 4 Prologue Terminal
Halo 4
Halo 4 Spartan Ops
Halo 4 War Games
Halo 4 Limited edition content
Halo Reach Last Cutscene(After N-6’s death)
Halo Reach Legendary Edition Letter
Halo Primordium future parts
Halo Silentium opening paragraph
Halo 4 Forward Unto Dawn Older Lasky parts
Marketing
Halo 4 The Commisioning
Halo 4 xbox.com site(note this site has radio in the background hence why I am putting this here)
Eleventh Hour Reports
Halo 3’s Believe(failed cover up by ONI)
Weird Stuff
Halseys Journal is put away, away from the hands of Serin Osman, due to a date on the ONI Envelope that says 1 June 2553
Cortana being alone for about 4 years.
> Well everythings pretty much been mentioned but heres a full list of post war content, Include the final cutscenes from Halo 3
>
> Main stuff
> Halo 3 Voi memorial cutscene
> Halo Evolutions The impossible life and the possible death of Preston J. Cole
> Halo Evolutions From the Office of Dr. William Arthur Iqbal
> Halo Evolutions The Return
> First Strike Adjunct Section Tug O’ War
> First Strike Adjunct Section Petra
> <mark>Grasslands</mark>
> The Thursday War
> Mortal Dictata
> Halo Spartan Assualt
> Halo Initiation
> Halo 4 Prologue Terminal
> Halo 4
> Halo 4 Spartan Ops
> Halo 4 War Games
> Halo 4 Limited edition content
> Halo Reach Last Cutscene(After N-6’s death)
> Halo Reach Legendary Edition Letter
> Halo Primordium future parts
> Halo Silentium opening paragraph
> Halo 4 Forward Unto Dawn Older Lasky parts
>
> Marketing
> Halo 4 The Commisioning
> Halo 4 xbox.com site(note this site has radio in the background hence why I am putting this here)
> Eleventh Hour Reports
> Halo 3’s Believe(failed cover up by ONI)
>
> Weird Stuff
> Halseys Journal is put away, away from the hands of Serin Osman, due to a date on the ONI Envelope that says 1 June 2553
*Glasslands.
But thanks for the info. 
> > Well everythings pretty much been mentioned but heres a full list of post war content, Include the final cutscenes from Halo 3
> >
> > Main stuff
> > Halo 3 Voi memorial cutscene
> > Halo Evolutions The impossible life and the possible death of Preston J. Cole
> > Halo Evolutions From the Office of Dr. William Arthur Iqbal
> > Halo Evolutions The Return
> > First Strike Adjunct Section Tug O’ War
> > First Strike Adjunct Section Petra
> > <mark>Grasslands</mark>
> > The Thursday War
> > Mortal Dictata
> > Halo Spartan Assualt
> > Halo Initiation
> > Halo 4 Prologue Terminal
> > Halo 4
> > Halo 4 Spartan Ops
> > Halo 4 War Games
> > Halo 4 Limited edition content
> > Halo Reach Last Cutscene(After N-6’s death)
> > Halo Reach Legendary Edition Letter
> > Halo Primordium future parts
> > Halo Silentium opening paragraph
> > Halo 4 Forward Unto Dawn Older Lasky parts
> >
> > Marketing
> > Halo 4 The Commisioning
> > Halo 4 xbox.com site(note this site has radio in the background hence why I am putting this here)
> > Eleventh Hour Reports
> > Halo 3’s Believe(failed cover up by ONI)
> >
> > Weird Stuff
> > Halseys Journal is put away, away from the hands of Serin Osman, due to a date on the ONI Envelope that says 1 June 2553
>
> *Glasslands.
>
> But thanks for the info.
Autocorrect does that.
The creation of The Monument to Master Chief from the ‘Believe’ videos
> The creation of The Monument to Master Chief from the ‘Believe’ videos
The Believe campaign is noncanon.
> > The creation of The Monument to Master Chief from the ‘Believe’ videos
>
> The Believe campaign is noncanon.
It still is canon as it is a cover by ONI but its hard to believe if anyone believes it as the real story.
And also yea, I made the list on my phone. xD Sorry about the mistake. Autocorrect. Thought I caught them all xD
Oh and damn forgot about Halo Legends Origins part 1 and 2