Whole psyllium husk will take care of the constipation/fiber very nicely. I usually use two handfuls with a half liter of water and chug it.

As far as variety, focus on what you can eat, not what you can't. Low carb tortillas are readily available. Coat with olive oil, microware for 2 minutes or so, and you have chips, pizza crust, whatever, for about 6g of carbs.

I've been low carb for many years. It works great.