Scooby-Doo! Mystery Incorporated - Season 1, Episode 11 - The Secret Serum (October 11th, 2010)
Written by Jed Elinoff & Scott Thomas
Directed by Curt Geda
There are several instances where I didn't point out the all-seeing eye symbol on the bookshelves, but it is shown more than 20 times. There is also a scene where the Scooby gang visits a blood bank in this episode.
Velma's mother shows up throughout the entire series wearing a necklace with an all-seeing eye on it. These episodes include:
Season 1, Episode 1 - Beware the Beast from Below (First Aired: April 5th, 2010 / Reaired: July 12th, 2010)
Season 1, Episode 5 - The Song of Mystery (August 9th, 2010)
Season 1, Episode 6 - The Legend of Alice May (August 16th, 2010)
Season 1, Episode 8 - The Grasp of the Gnome (August 30th, 2010)
Season 1, Episode 10 - Howl of the Fright Hound (October 4th, 2010)
Season 1, Episode 12 - Shrieking Madness (October 18th, 2010)
Season 1, Episode 16 - Where Walks Aphrodite (May 17th, 2011)
Season 1, Episode 20 - The Siren's Song (June 14th, 2011)
Season 1, Episode 22 - Attack of the Headless Horror (June 28th, 2011)
Season 1, Episode 23 - A Haunting in Crystal Cove (July 5th, 2011)
Season 1, Episode 26 - All Fear the Freak (July 26th, 2011)
Season 2, Episode 16 - Aliens Among Us (March 25th, 2013)
Season 2, Episode 20 - Stand and Deliver (March 28th, 2013)
Season 2, Episode 23 - Dark Night of the Hunters (April 3rd, 2013)
Season 2, Episode 24 - Gates of Gloom (April 4th, 2013)
A biker gang called the Wild Brood has a logo of an eye. There is also an old man wearing a necklace with the ouroboros symbol (snake/dragon eating it's own tail) which is sometimes depicted with the all-seeing eye. The ouroboros has many meanings depending on the culture, but it is a representation of "as above so below" in occult circles:
Season 1, Episode 15 - The Wild Brood (May 10th, 2011)
The old man that wears the necklace with the ouroboros plays a larger role:
Season 1, Episode 18 - The Dragon's Secret (May 31st, 2011)
Multiple instances of one-eye symbolism:
Season 2, Episode 5 - The Hodag of Horror (August 3rd, 2012)
The bookshelves with the all-seeing eye on them appear once again:
Season 2, Episode 19 - The Devouring (March 27th, 2013)
Nibiru and/or the Anunnaki are referenced multiple times throughout season 2, especially in the following episodes:
Season 2, Episode 13 - Wrath of the Krampus (August 15th, 2012)
Season 2, Episode 20 - Stand and Deliver (March 28th, 2013)
Season 2, Episode 25 - Through the Curtain (April 5th, 2013) - also contains a few instances of one-eye symbolism
https://www.imdb.com/title/tt1660055/
https://en.wikipedia.org/wiki/List_of_Scooby-Doo!_Mystery_Incorporated_episodes
