Someone on the Minecraft Forums Discus chat group just asked about the zero Minecraft seed.
This has been discussed before. Albeit quite some time ago so I'm going to post the list again.
Here's the thing. The Minecraft seed input routine interprets a blank or an entry of 0 (zero not O) as requesting a randomly generated seed to be used to create a new world even though zero is a perfectly acceptable seed value.
Now if any text string is entered the string is sent to Java's hashCode() function which uses an algorithm to convert the text into a specific numeric value.
This action bypasses the zero input test and the world generator will use zero as its seed.
One other thing. The Minecraft Seed input dialog will only allow 32 characters to be entered so usable strings for this are limited to that length.
Here's the list of zero seed strings that I know of.
Entering any of these strings (without the "s) will produce the zero seed world.
Frankly I think it's somewhat boring, but that's just my opinion.
If you want a spawn in plains near Extreme Hills, a river, a Roofed Forest, and Ocean shore then this is the seed for you.
Notice the Seed definition shown in the upper left corner of the PCMC v 1.13.1 map below.
Well, It's not as boring as I thought.
I just created the world in 1.13.1 using "pollinating sandboxes" (not that it matters which string you use) and spawned just to the east of a double ravine in the shape of a giant X carved in the ground at the edge of the Roofed Forest.
There's a third ravine between spawn and the ocean shore.
There are pumpkins right at one end of one of the ravines.
(I grow pumpkins to make jackolanterns to light mines and caves to show which way out.)
There are horses, cows, pigs, and sheep near spawn.
Actually likes an easy world to start in.
I just created "pollinating sandboxes" in release 1.16.2.
The one thing I noticed is that the pumpkins are no longer near the ravine.
A search for "pumpkin" named blocks with Minutor produced 3 hits.
The green circles in the lower right of the image below are their locations.