Mortal Kombat 11

To get this really fast press on the main menu and change "Rounds to win" from 2 to 1. Then go to local and play against a second controller or the CPU, if you're fighting the CPU I'd highly suggest setting it to "Very Easy", making all the achievements far easier! Select Kollector and spam + and + or , when "Finish Him" appears on the screen perform your fatality.

1st Fatality (Close): Down, Down, Down, Down,
2nd Fatality (Close): Down, Forward, Back,

Video for Reference:

At the main menu press change rounds to win from 2 to 1.
Then go to Fight and select Local. Press to switch the opponent type from a second player to the CPU (or use a second controller for a guaranteed win).
Select Kollector and an opponent, loadouts don't matter.
Then once you get to the end of the Match when "FINISH HIM" comes onto the screen input one of these combination at the specified distance:
-For the Kollection (Close/right next to the opponent)
-Head Lantern (Close/right next to the opponent)

*Directional inputs are assuming you are on the left side of the Screen*

In the options (press Select) set number of rounds to 1 and when selecting opponent set AI difficulty to 'Very Easy' (can also use a second controller if available).

Hit the enemy until their health bar is drained at which point 'FINISH HIM' will appear on screen. Position your character in the appropriate spot and input the following commands:

For The Kollection (Close) - Down, Down, Down, Down, B
Head Lantern (Close) - Down, Forward, Back, X

Then when the points are tallied hit 'Retry' to restart and perform the second finishing move.

In this video guide I will show you how to perform two different fatalities with Kollector. For the first 10 characters I just used the klassic towers to get the achievement progress for I Want It All. Make sure to put it on very easy to make things quicker. Also pick the shortest tower.
After getting your I Want It All achievement the method with be a lot faster. Once in the main menus press the start button to go into the options menu. Scroll down to change the rounds to win to one. Then back out, go into the fight menu, select local, make sure to press X to turn on the CPU, and then select your character. You only have the one health bar to deal with to get to the fatality.
Achievement progress also counts if AI do a fatality.

For The Kollection (Close) - Down, Down, Down, Down, B
Head Lantern (Close) - Down, Forward, Back, X