https://www.who.int/news-room/fact-sheets/detail/natural-toxins-in-food

I'm sure you'll accept this as a source since you're directly asking about my responses for it, so we can just go over the page together if that makes you feel better. This page from the WHO describes 8 types of toxins found in plants, and we can just go over them one at a time.

Aquatic Biotoxins

Toxins formed by algae in the ocean and fresh water are called algal toxins.

Algae is generally not food, and even more generally not considered an herb or spice. Interestingly, "Shellfish such as mussels, scallops and oysters are more likely to contain these toxins than fish," so I hope your plant-free diet also avoids most forms of sea-food, as they can contain these kinds of toxins.

Cyanogenic glycosides

Cyanogenic glycosides are phytotoxins (toxic chemicals produced by plants) which occur in at least 2000 plant species, of which a number of species are used as food in some areas of the world. Cassava, sorghum, stone fruits, bamboo roots and almonds are especially important foods containing cyanogenic glycosides.

This is important, but I'm pretty sure the examples given here aren't herbs and spices again.

Furocoumarins

These toxins are present in many plants such as parsnips (closely related to carrots and parsley), celery roots, citrus plants (lemon, lime, grapefruit, bergamot) and some medicinal plants.

Once again, not really herbs or spices.

Lectins

Many types of beans contain toxins called lectins, and kidney beans have the highest concentrations – especially red kidney beans. As few as 4 or 5 raw beans can cause severe stomachache, vomiting and diarrhoea. Lectins are destroyed when the dried beans are soaked for at least 12 hours and then boiled vigorously for at least 10 minutes in water.

Only a warning about lectins in beans, and I'm explicitly told that they're destroyed by cooking.

Mycotoxins

Mycotoxins are naturally occurring toxic compounds produced by certain types of moulds. Moulds that can produce mycotoxins grow on numerous foodstuffs such as cereals, dried fruits, nuts and spices.

Here we have another concern for plants, but I'm pretty sure moldy food is a problem no matter what kind of food you start with.

Solanines and chaconine

All solanacea plants, which include tomatoes, potatoes, and eggplants, contain natural toxins called solanines and chaconine (which are glycoalkaloids). While levels are generally low, higher concentrations are found in potato sprouts and bitter-tasting peel and green parts, as well as in green tomatoes.

Not in herbs and spices, and the higher concentrations you might actually be worried about are parts of the plant you don't eat.

Poisonous mushrooms

Need I say more? Mushrooms can be very dangerous, but they aren't actually plants.

Pyrrolizidine alkaloids

Pyrrolizidine Alkaloids (PAs) are toxins produced by an estimated 600 plant species. The main plant sources are the families Boraginaceae, Asteraceae and Fabaceae. Many of these are weeds that can grow in fields and contaminate food crops.

Again, not in the plants you would usually eat.

And so now I've gone over all the types of toxins found in plants provided by jet, and I'm sure you can agree that it doesn't say a lot about herbs and spices being inherently unhealthy. All I can ask now is for some kind of basis for your belief that all plants contain toxins, and how whatever standard you're using to come to that conclusion wouldn't also apply to meat or mushrooms or whatever else you're trying to eat.