u/Jarfolomew

Royal Rumble 91

WWF Championship Match: Mr. Perfect (c) vs Sgt. Slaughter

Royal Rumble 93

WWF Championship Match: Shawn Michaels (c) vs Razor Ramon

Royal Rumble 94

WWF Championship Casket Match: Razor Ramon (c) vs Undertaker

Royal Rumble 95

WWF Championship Match: Razor Ramon (c) vs Bret Hart

Royal Rumble 96

WWF Championship Match: Razor Ramon (c) vs Undertaker

Royal Rumble 97

WWF Championship Match: Hunter Hearst Helmsley (c) vs Shawn Michaels

Royal Rumble 98

WWF Championship Casket Match: The Rock (c) vs Undertaker

Royal Rumble 99

WWF Championship "I Quit" Match: Ken Shamrock (c) vs The Rock

Royal Rumble 00

WWF Championship Street Fight: Chris Jericho and/or Chyna (c) vs Cactus Jack

Royal Rumble 01

WWF Championship Match: Chris Benoit (c) vs Triple H

Royal Rumble 02

Undisputed Championship Match: Edge (c) vs The Rock

Royal Rumble 03

No Intercontinental or United States Champions

Royal Rumble 04

WWE Championship Match: Big Show (c) vs Hardcore Holly

World Heavyweight Championship Last Man Standing Match: Randy Orton (c) vs Shawn Michaels

Royal Rumble 05

WWE Championship Match: John Cena (c) vs Kurt Angle vs Big Show

World Heavyweight Championship Match: Shelton Benjamin (c) vs Randy Orton

Royal Rumble 06

WWE Championship Match: Shelton Benjamin (c) vs John Cena

World Heavyweight Championship Match: Booker T (c) vs Mark Henry

Royal Rumble 07

World Heavyweight Championship Match: Chris Benoit (c) vs Mr. Kennedy

WWE Championship Last Man Standing Match: Jeff Hardy (c) vs Umaga

Royal Rumble 08

World Heavyweight Championship Match: MVP (c) vs Rey Mysterio

WWE Championship Match: Jeff Hardy (c) vs Randy Orton (title swap)

Royal Rumble 09

World Heavyweight Championship Match: CM Punk (c) vs JBL

WWE Championship No DQ Match: Shelton Benjamin (c) vs Edge

Royal Rumble 10

WWE Championship Match: The Miz (c) vs Randy Orton

World Heavyweight Championship Match: Drew McIntyre (c) vs Rey Mysterio

Royal Rumble 11

World Heavyweight Championship Match: Kofi Kingston (c) vs Dolph Ziggler

WWE Championship Match: Daniel Bryan (c) vs Randy Orton

Royal Rumble 12

World Heavyweight Championship Steel Cage Match: Cody Rhodes (c) vs Big Show vs Mark Henry

WWE Championship Match: Jack Swagger (c) vs Dolph Ziggler

Royal Rumble 13

World Heavyweight Championship Last Man Standing Match: Wade Barrett (c) vs Big Show

WWE Championship Match: Antonio Cesaro (c) vs The Rock

Royal Rumble 14

WWE World Heavyweight Championship Match: Dean Ambrose or Big E. (c) vs John Cena

Royal Rumble 15

WWE World Heavyweight Championship Match: Rusev or Bad News Barrett (c) vs John Cena vs Seth Rollins

Royal Rumble 17

Universal Championship No Holds Barred Match: Chris Jericho (c) vs Roman Reigns

WWE Championship Match: Dean Ambrose (c) vs John Cena

Royal Rumble 18

WWE Championship Handicap Match: Bobby Roode (c) vs Kevin Owens & Sami Zayn

Universal Championship Match: The Miz (c) vs Kane vs Braun Strowman

Royal Rumble 19

WWE Championship Match: Rusev (c) vs AJ Styles

Universal Championship Match: Bobby Lashley (c) vs Finn Balor

Royal Rumble 20

Universal Championship Strap Match: Shinsuke Nakamura (c) vs Daniel Bryan

Royal Rumble 21

WWE Championship Match: Bobby Lashley (c) vs Goldberg

Universal Championship Last Man Standing Match: Big E. (c) vs Kevin Owens

Royal Rumble 22

Universal Championship Match: King Nakamura (c) vs Seth Rollins

WWE Championship Match: Damian Priest (c) vs Bobby Lashley

Royal Rumble 23

Undisputed WWE Universal Championship Match: Gunther or Austin Theory (c) vs Kevin Owens

Royal Rumble 24

Undisputed WWE Universal Championship Match: Logan Paul (c) vs Randy Orton vs AJ Styles vs LA Knight

Royal Rumble 25

WWE Championship Ladder Match: Shinsuke Nakamura (c) vs Kevin Owens

Royal Rumble 26

WWE Championship Match: Carmelo Hayes (c) vs Sami Zayn

I did something similar to WrestleMania and SummerSlam last year. Basically asking what if the Intercontinental & United States Champions at the time were World Champs during every Backlash event.

Backlash 99

WWF Championship No Holds Barred Match: The Godfather (c) vs The Rock

Backlash 00

WWF Championship Match: Chris Benoit (c) vs The Rock

Backlash 01

WWF, Intercontinental & Tag Team Championship Winner Take All Match: Triple H (WWF) & Steve Austin (IC) vs The Brothers of Destruction (Tag)

So pretty much no difference aside a title swap.

Backlash 02

Undisputed Championship Match: Rob Van Dam (c) vs Hulk Hogan

Backlash 03

No Intercontinental or United States Champions at the time.

Backlash 04

World Heavyweight Championship Match: Randy Orton (c) vs Triple H vs Shawn Michaels

Backlash 05

World Heavyweight Championship Match: Shelton Benjamin (c) vs Triple H

Backlash 06

WWE Championship Match: Shelton Benjamin (c) vs Triple H vs Edge

Backlash 07

World Heavyweight Championship Last Man Standing Match: Chris Benoit (c) vs Batista

WWE Championship Match: Santino Marella (c) vs Shawn Michaels vs Edge vs Randy Orton

Backlash 08

World Heavyweight Championship Match: MVP (c) vs Edge

WWE Championship Elimination Match: Chris Jericho (c) vs Triple H vs John Cena vs JBL

Backlash 09

WWE Championship 6-Man Tag: MVP (c), Batista & Shane McMahon vs Legacy

World Heavyweight Championship Last Man Standing Match: Rey Mysterio (c) vs Edge

Backlash 16

WWE Championship Match: The Miz (c) vs AJ Styles

Backlash 17

WWE Championship Match: Kevin Owens (c) vs Jinder Mahal

Backlash 18

WWE Championship No Holds Barred Match: Jeff Hardy (c) vs Shinsuke Nakamura

Backlash 20

Universal Championship Handicap Match: AJ Styles (c) vs The Miz & John Morrison

WWE Championship Match: Apollo Crews (c) vs Bobby Lashley

Backlash 21

WWE Championship Match: Sheamus (c) vs Drew McIntyre vs Braun Strowman

Universal Championship Match: Apollo Crews (c) vs Cesaro

Backlash 22

Theory or Ricochet & The Usos vs Drew McIntyre & RK-Bro

Backlash 24

World Heavyweight Championship Match: Sami Zayn (c) vs Jey Uso

WWE Championship Match: Logan Paul (c) vs AJ Styles

Backlash 25

WWE Championship Match: Jacob Fatu (c) vs Randy Orton

Backlash 26

World Heavyweight Championship Match: Penta (c) vs Jacob Fatu