Submarine

Submarine is a TSS → TSD → PC opener developed by Eternalaws and Not Kaiyon, given the name "Submarine" due to its shape roughly resembling a Submarine submerging into water. This opener can be performed with an early L/J in the first bag. This opener leaves a relatively clean and easy to downstack board state thanks to multiple donation methods in the second bag.

Variant 1
This is the main route to submarine with easy to spot perfect clear patterns. Requires relatively early LJ or LZ.

PC Chance - 93.33%
If you have a late I and/or receive garbage when going for PC you can opt for a TSS into Tetris.

Variant 2
This variant rarely ends up with an extra O after perfect clear. Requires relatively early OL or OZ.

PC Chance - 94.52%
Note: Not all pc patterns are visualized, full list of pc patterns Link -> 

Variant 3
While not often buildable, this variant almost guarantees a perfect clear everytime with easy to spot patterns. J→Z→L

PC Chance - 99.25%
Note: Not all pc patterns are visualized, full list of pc patterns Link -> 

Variant 4
This variant mainly consists of LJI on the left but sometimes you can get the same field from doing a donation Tspin double and then insert the I piece on left when you get a late I.

PC Chance - 95.4%
There are possible Tspin single or double solutions

Note: Not all pc patterns are visualized, full list of pc patterns Link -> 

S Prop Variant
O→L

TSD Followup
J→S

The third bag TSD variant is only dependent on a J before S thanks to multiple helpful L spins.

There is one possible perfect clear pattern for this follow up at only 7.14% chance but it is easy to spot.

Non PC Variant
This pattern has a very high succession rate thanks to multiple alt formations.

Possible Followups
J→S/Z, L→O

L→S→Z, O→J

You can put a Z piece on the right to freestyle a TSD with basic stacking on the left.

Mirroring submarine
It is advisable to shift I for submarine while mirroring rather than using the usual form for lower KPP (Keypresses Per Piece) on the first bag. Variant 1,2 and 3 are available for shifted I while other variants cannot be done. Shifted I has an exclusive variation too.

Variant exclusive to shifted I
The S piece in the first pattern can be tucked in after L and J are placed while the J piece in the second pattern can be spun in after S piece is placed.

PC Chance - 96.47%
There are 5minimal solutions: