Here are four extremely poisonous mushrooms that can sometimes be found around homes or in gardens:

1. Amanita phalloides (Death Cap Mushroom) – This mushroom is responsible for the majority of mushroom poisoning deaths worldwide. It looks deceptively similar to edible mushrooms, but it contains deadly toxins (amatoxins) that can cause liver and kidney failure.

2. Amanita virosa (Destroying Angel) – Like the Death Cap, the Destroying Angel contains amatoxins and is highly toxic. It appears white and has a delicate, innocent appearance, but ingestion can lead to fatal liver and kidney damage.

3. Galerina marginata (Funeral Bell) – This small, brown mushroom can grow in wood or on decaying tree trunks. It contains the same toxins as the Death Cap and Destroying Angel and can be deadly if eaten.

4. Conocybe filaris – This mushroom is similar in appearance to the Death Cap and also contains potent amatoxins. It can cause severe liver damage and death if consumed.

If you encounter any mushrooms around your house, it's important not to touch or ingest them unless you are absolutely sure of their identity. Many toxic mushrooms closely resemble edible ones, and it's always safer to err on the side of caution.