Crowbar

Crowbar is an opener loop by stickmancomic. Every bag can always be stacked. The loop consists of two T-Spin Doubles, a Tetris and a Perfect Clear, with possibility of extra T-Spins or Tetrises.

First Bag
You will always be able to stack either the 1st bag setup or its mirror. Do the first one if L comes before J, and the second if J comes before L.

Second Bag
You will always be able to stack the 2nd bag this way. The placement of OSZ is interchangeable. There is a possibility of a T-Spin Single if either J or T is reasonably late.

Third Bag
You will always be able to stack the 3rd bag this way.

Fourth Bag
Again, you will always be able to stack the 4th bag this way. The placement of LSZ is interchangeable.

Fifth Bag
There is a 100% PC chance, though you only need 1 solution. The second solution however may give you a T-Spin Double.

Crowbar v2
Crowbar v2 is a more efficient loop compared to its predecessor. Notably, the T-Spin Single in the 2nd bag is guaranteed and it is possible to retain Back-to-Back throughout loops. However, the 1st bag may fail for some queues and the 3rd bag may require 180-degree rotations not present in official games.

First Bag
You will be able to stack the first bag if TSZ is not early. Specifically, it will fail if TSZ comes before LOJ. There is a possibility of a T-Spin Mini Single. Considering mirrors, you will have a 95.00% chance of stacking the first bag, or 66.67% if a T-Spin Mini Single is required.

Second Bag
You will always be able to stack the 2nd bag this way.

Third Bag
If you have 180 degree rotations, you will always be able to stack the 3rd bag this way. The placement of LJZ is interchangeable.

Fourth Bag
The last two bags of the loop are the same as the original. You will always be able to stack the 4th bag this way.

Fifth Bag
There is a 100% PC chance, though you only need 1 solution. The second solution however may give you a T-Spin Double.