series

Iron Horse series - The Hat Man

Look here.

Tantabus Mk. II series - Rambling Writer

"Tantabus Mk. II"
"Aunthood Issues"
"Tantabus Communication Protocol"
"How the Tantabus Parses Sleep"

Past Sins series - Pen Stroke
"First Hours" (
"Past Sins" (original)
"In The Family" trilogy
-"Trinkets"
-"Nightmare or Nyx"
-"Winter Bells"
"The Road Home"
"Glimpses"

1) Bride of Discord series - disneyfanatic2394
"Bride of Discord"
"I Love Ya to the Core"
"Discord Dating Game"
"Daughter of Discord"
First chapter of "Son-in-Law of Discord"
"CMC: The Next Generation"
-"Hearth's Warming Chaos" happens after the chapter "Words, Words, Words", before the chapter "Until We Meet Again", a year before chapter "Gift of the Raspberry Lemon"
Rest of "Son-in-Law of Discord"

So I found this stories. They are all different authors, but I feel as if these stories can be a series.
"Through Her Eyes" by Zaid ValRoa (The unofficial prequel)
"Picnic Peepers" by Art Inspired