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if you see anything you like and want to know how I make them just post the picture here.
This one is for you Alpine as requested:
I get some garden soil and make it a rough shape line a wall the shape of the pot and a bit higher than intended height. Very rough,,,and thick just enough to hold the cement when plastered inside.
this soil initially was thicker but even this is fine. The soil must be dump.

then I make sure the lower section of the soil has like 1cm nice and smooth edge...the walls are somewhat well shaped and then
I get some think flat and press on top to make the top surface flat and the top 0.5-1cm vertical almost...I check it up and smoothen the top edge and make sure it is horizontal. Some time it does not
I ger some stone with rough surface and press it on the inside of the mold to create stone like look.
happen...but with time you will be an expert...if it does not happen I grind them with an angle grinder and they become smooth.
Then I make a mix of 1cement to 2 very fine building sand...make the mix hard or it will slide with gravity.
Some time I add coloring agent in the mox, some time I add it on top. I use iron oxide or PVA paint mixed into the mix by substituting some of the water with it. Just make sure you buy the darkest color since it gets very light when You add it to the cement.
Take small pieces and start pressing them next to each other so you monitor from the side the thickness of the plaster. then smooth it with a spon.
ssome I just paint on the outside with PVA, and before it fries I wash it out so it remains only in the inside spaces...and I use different colors. Then I paint with varnish for stones. Inside I paint with rubber pool paint so the roots for acid loving plants dont touch the concrete.
when it is dry you just wash the soil off with a brush.
some molds I make inverted...smooth and well shaped and plaster on top.

some time I use a ballon for this pots





I have many different methods...and pots.