Here's a way of sewing in-seam pockets entirely on the front piece of the garment - reliably flat, you can add a zip and super easy to French seam the pocket bags together. Result!
There doesn't seem to be a recognised name for this type of in-seam pocket, although I've seen it referred to as "the couture method" *
Here's the pdf if you want to download it:
In seam pocket: couture method
.pdf
Download PDF • 1.09MB
* @sewitwithdi on Instagram