Oyster mushrooms are known predators of nematodes. They are not mentioned in the above wiki, but their own confirms that they exploit toxins to capture and feed.
There is an ISO definition of vegan (23662:2021) but it seems to cost $88 and then I emerged from the rabbit hole.
Most vegan adhere to a more practical and pragmatic definition, like this one, from the association founded by the veganism-word initiators:
> Most vegan adhere to a more practical and pragmatic definition
And wow yes. ‘I’m a ISO standard vegan’ isn’t something I’ve heard and it has probably never happened.