| Name | Character | Episodes |
|---|---|---|
| Derek Waters | Himself - Host / Various Characters | 70 |
| Maria Blasucci | Various | 10 |
| Tymberlee Hill | Various | 9 |
| Sarah Burns | Various | 8 |
| Adam Nee | Various | 7 |
| Tim Baltz | Various | 3 |
| Mort Burke | Various | 3 |
| Tony Hale | Edward Cope | 2 |
| Eric Edelstein | Himself - Narrator | 2 |
| Allan McLeod | Himself - Narrator | 2 |
| Matt Gourley | Himself - Narrator | 2 |
| Tommy Blacha | Self - Narrator | 2 |
| Colin Hanks | Gordon Cooper | 1 |
| Colin Hanks | Ernest Thompson Seton | 1 |
| Colin Hanks | Fred Rogers | 1 |
| Maya Rudolph | Griselda Blanco | 1 |
| Colin Hanks | Charles Dickens | 1 |
| Lin-Manuel Miranda | Himself | 1 |
| Will Ferrell | Roald Dahl | 1 |
| Juno Temple | Sybil Luddington | 1 |
| Aubrey Plaza | Aaron Burr | 1 |
| Aubrey Plaza | Sacagawea | 1 |
| Jason Momoa | Jean Lafitte | 1 |
| Nathan Fillion | Wernher von Braun | 1 |
| Laura Dern | Nellie Bly | 1 |
| Haley Joel Osment | Kid Blink | 1 |
| Kirsten Dunst | Agatha Christie | 1 |
| Dennis Quaid | Lucky Luciano | 1 |
| Josh Hartnett | Clark Gable | 1 |
| Jesse Plemons | Edgar Allan Poe | 1 |
| Jesse Plemons | William Kenward | 1 |
| Giancarlo Esposito | Andrés Pico | 1 |
| Jack Black | William Mulholland | 1 |
| Jack Black | Vincenzo Peruggia | 1 |
| Jack Black | Elvis Presley | 1 |
| Adam Scott | John Wilkes Booth | 1 |
| Owen Wilson | John Harvey Kellogg | 1 |
| Will Forte | Edwin Booth | 1 |
| David Harbour | Vietnam Memorial Head | 1 |
| Winona Ryder | Mary Dyer | 1 |
| Simon Helberg | Frank M. Robinson | 1 |
| Kat Dennings | Kentucky Daisey | 1 |
| Kristen Wiig | Patty Hearst | 1 |
| Octavia Spencer | Harriet Tubman | 1 |
| Parker Posey | Mary Phelps Jacob | 1 |
| Bob Odenkirk | Richard Nixon | 1 |
| Bob Odenkirk | The Guy | 1 |
| Connie Britton | Patricia Shaheen | 1 |
| Michael Cera | Maurice Cohen | 1 |
| Michael Cera | John Endicott | 1 |
| Alfred Molina | Sir Arthur Conan Doyle | 1 |
| Michael McKean | Carl Laemmle | 1 |
| Terry Crews | Donald 'Cinque' DeFreeze | 1 |
| Terry Crews | Joe Louis | 1 |
| Jason Schwartzman | Ralph Nader | 1 |
| Adrianne Palicki | Kate Warne | 1 |
| Johnny Knoxville | Ponce De Leon | 1 |
| Johnny Knoxville | Marshall Ratliff | 1 |
| Johnny Knoxville | Johnny Cash | 1 |
| Jason Ritter | Elisha Gray | 1 |
| Jason Ritter | Robert Wilson | 1 |
| Jason Ritter | Stetson Kennedy | 1 |
| Jason Ritter | Art Heist Investigator | 1 |
| Sam Rockwell | Bugsy Siegal | 1 |
| Bill Hader | John Pemberton | 1 |
| Jenny Slate | Herself - Storyteller | 1 |
| Jenny Slate | Herself - Narrator | 1 |
| Jack McBrayer | General Andrew Jackson | 1 |
| Jack McBrayer | 1 | |
| Jack McBrayer | H.R. Haldeman | 1 |
| Jack McBrayer | Clarence Darrow | 1 |
| Jack McBrayer | Alan Freed | 1 |
| Jason Alexander | William Tweed | 1 |
| Alia Shawkat | Alexander Hamilton | 1 |
| Alia Shawkat | Virginia Hall | 1 |
| Paget Brewster | Herself - Narrator | 1 |
| Noah Wyle | Thomas Nast | 1 |
| Ryan Phillippe | Benjamin Hayes | 1 |
| Dave Foley | Alexis Pulaski | 1 |
| Greg Kinnear | Thaddeus Lowe | 1 |
| Christopher Meloni | Othniel Marsh | 1 |
| Chelsea Peretti | Ann Druyan | 1 |
| Trace Lysette | Sylvia Rivera | 1 |
| Trace Lysette | Elizabeth Eden | 1 |
| Blake Anderson | Alexey Leonov | 1 |
| Vanessa Bayer | Mary Gillespie | 1 |
| Clint Culp | Policeman | 1 |
| Steven Weber | Lomax | 1 |
| Andy Daly | Teddy Roosevelt | 1 |
| Bradley Whitford | William Jennings Bryan | 1 |
| Rob Riggle | J. Edgar Hoover | 1 |
| Martin Starr | Art Thief | 1 |
| Matt Walsh | KKK Member | 1 |
| Matt Walsh | Joseph Pulitzer | 1 |
| Nick Offerman | Johnny Cool | 1 |
| Taran Killam | D.B. Cooper | 1 |
| Taran Killam | William Clark | 1 |
| Taran Killam | Frédéric Auguste Bartholdi | 1 |
| Chris Parnell | Thomas Edison | 1 |
| Chris Parnell | Jim Bowie | 1 |
| Chris Parnell | King Charles II | 1 |
| Jaleel White | Bass Reeves | 1 |
| Jaleel White | Grandmaster Caz | 1 |
| Jayma Mays | Florence Schaffner | 1 |
| Zach Gilford | Jim Abbott | 1 |
| Liev Schreiber | Victor Lustig | 1 |
| Jenna Fischer | Katharine Wright | 1 |
| Justin Long | Arno Penzias | 1 |
| Sophia Bush | Bonnie Raines | 1 |
| Randall Park | Himself - Storyteller | 1 |
| Jason Mantzoukas | Pope | 1 |
| Patton Oswalt | Mac Brazel | 1 |
| Lauren Lapkus | Normal Woman | 1 |
| Adam Devine | Pavel Belyayev | 1 |
| Kumail Nanjiani | Lakota Chief | 1 |
| Will Sasso | Frank Nitti | 1 |
| Brett Gelman | Art Thief | 1 |
| Brett Gelman | Joseph Pulitzer | 1 |
| Jordan Peele | Percy Julian | 1 |
| Kevin Nealon | The Grand Dragon | 1 |
| Ike Barinholtz | August Spies | 1 |
| David Koechner | John Pastore | 1 |
| Richard Riehle | Ralph Himmelsbach | 1 |
| Richard Riehle | James Roche | 1 |
| Natasha Leggero | Elizabeth Bisland | 1 |
| Natasha Leggero | Herself - Narrator | 1 |
| Shannon Woodward | Ida Tarbell | 1 |
| Thomas Lennon | Major Marcel | 1 |
| Kimiko Glenn | Maya Lin | 1 |
| Colton Dunn | Himself - Narrator | 1 |
| Zach Woods | Lee Duncan | 1 |
| Stephen Merchant | F**kin' President Lincoln | 1 |
| Stephen Merchant | Abraham Lincoln | 1 |
| Retta | Sylvia Robinson | 1 |
| Lisa Bonet | Mary Ellen Pleasant | 1 |
| Lisa Bonet | Rosa Parks | 1 |
| June Diane Raphael | Isabella Stewart Gardner | 1 |
| Donald Faison | Joe Louis | 1 |
| Chris Romano | Himself - Narrator | 1 |
| Rob Corddry | George Washington | 1 |
| Fred Willard | Deep Throat | 1 |
| Joe Lo Truglio | Al Capone | 1 |
| Jake Johnson | William B. Travis | 1 |
| Michaela Watkins | Nurse | 1 |
| David Wain | Himself - Narrator | 1 |
| Tony Hale | James Monroe | 1 |
| Tony Hale | Meriwether Lewis | 1 |
| Rob Huebel | Governor Trevino | 1 |
| Rob Huebel | Pat Garrett | 1 |
| Eric Edelstein | Museum Guard | 1 |
| Tim Heidecker | Cop | 1 |
| Tim Heidecker | Max Schmeling | 1 |
| Maestro Harrell | Louis Armstrong | 1 |
| Charlie Finn | Cpt. 'Black Jack' Bonfield | 1 |
| Eric Falconer | Himself - Narrator | 1 |
| Steve Berg | Various | 1 |
| Questlove | Himself | 1 |
| Ken Marino | Theodore Roosevelt | 1 |
| Ken Marino | Masterpiece | 1 |
| Ken Marino | Harry Houdini | 1 |
| Luke Wilson | Will Keith Kellogg | 1 |
| Mark Proksch | Himself - Storyteller | 1 |
| Ellie Kemper | Nellie Bly | 1 |
| Henry Winkler | Zenas Fisk Wilber | 1 |
| John Ennis | John D. Rockefeller | 1 |
| Casey Wilson | Dolly Parton | 1 |
| Paul Rust | John Wojtowicz | 1 |
| Derek Waters | C.S. Forester | 1 |
| Artemis Pebdani | Herself - Narrator | 1 |
| Andre Royo | King Oliver | 1 |
| Christopher Jackson | Himself | 1 |
| Nathan Fielder | Bob Woodward | 1 |
| Nathan Fielder | John Lennon | 1 |
| Da'Vone McDonald | Big Bank Hank | 1 |
| Paul Scheer | Carl Sagan | 1 |
| Paul Scheer | Colonel Henry Ludington | 1 |
| Steve Little | Mark Twain | 1 |
| Horatio Sanz | Gen. Santa Anna | 1 |
| Ben Folds | Nathan Cherry | 1 |
| Ben Folds | Self | 1 |
| Kyle Mooney | Himself - Storyteller | 1 |
| Matt Besser | Edwin Stanton | 1 |
| Jon Daly | Kris Kristofferson | 1 |
| 'Weird Al' Yankovic | 1 | |
| 'Weird Al' Yankovic | Adolf Hitler | 1 |
| Aaron Takahashi | Frank Emi | 1 |
| Rich Fulcher | Self - Narrator | 1 |
| Rich Fulcher | Porter Wagoner | 1 |
| Ron Funches | Herc | 1 |
| Rachel Bloom | Herself - Storyteller | 1 |
| Timm Sharp | Billy the Kid | 1 |
| Raymond Ochoa | Various | 1 |
| Michael Coleman | Various | 1 |
| Lyric Lewis | 1 | |
| Claudia O'Doherty | Herself - Storyteller | 1 |
| Alison Rich | Herself - Storyteller | 1 |
| Moshe Kasher | Albert Parsons | 1 |
| Amber Ruffin | Herself - Narrator | 1 |
| Jonathan Ames | Junius Booth | 1 |
| Preston Flagg | Himself - Narrator | 1 |
| Jon Gabrus | Himself - Storyteller | 1 |
| J.D. Ryznar | Himself - Narrator | 1 |
| Grant Imahara | Frank Inouye | 1 |
| Anton Starkman | 1 | |
| Morgan Murphy | Herself - Narrator | 1 |
| Jennie Pierson | Herself - Storyteller | 1 |
| Joseph Billingiere | Various | 1 |
| John A. Lorenz | Lakota Indian | 1 |
| Corey Weber | Tim- The Cowboy | 1 |
| Mariah Iman Wilson | Claudette Colvin | 1 |
| Jerry Minor | Edgar Nixon | 1 |
| Kyle Kinane | Self - Narrator | 1 |
| Dave Grohl | Memphis Mafia Member | 1 |