What kind of idioms or proverbs are used to describe a small matter to set off another big event?

Get the whole picture from small details

From the initial small start, people can see how things will develop.

The fall of a leaf is enough to tell us that autumn is coming-a straw shows the direction of the wind.

Drop into the sea

Xiaoya and Chen Da

Shuichengyuan

Virtue makes a man a gentleman.

Drip wears away the stone-persistence is success.

Countless stars surround the moon ―― enjoying the respect and support of many capable people.

Safflowers must also be supported by green leaves.

A levee of a thousand miles, collapsed in an ant nest-a little carelessness may lead to great disaster; A small leak will sink a huge ship; If ignored, any small problem may lead to catastrophe.

Although the sparrow is small, it has all aspects.

Goose feathers are sent from afar, a trivial gift, but there is a heavy yearning behind it; What matters is not the gift, but the mind behind it.

Don't do evil, no matter how small it is; Don't forget to do good, no matter how insignificant it is.