Keto can lead to scurvy and kidney disease. Low carb diets are scientifically unsound. Medical professionals in the U.S. have rated diets like Atkins and Keto near the very bottom, and these are doctors who still eat meat. They rate veganism much higher than low carb diets, and only rate veganism lower than flexitarianism or vegetarianism due to being what they see as "too restrictive for some people."
If you're worried about carbs eat whole grains and avoid sugar and white flour.
Even the vegan, low(er) carb "Ec0-Atkins" still rates lower in both health, ease and taste than a traditional vegan diet. Vanity and marketing seem to be the only reasons people are buying into low-carb and there's literally zero foundation for them in health or medicine.
If you're asking simply because you just don't want to eat rice or pasta again today and it's purely for varietal reasons, you could eat nuts, seeds, celery or raw broccoli and hummus, pickled beets or kimchi, or a cacao and nut butter snack bar of some sort.