When 'all' is a pronoun, it can come with both singular and plural nouns. There are 63 meanings listed in oed's entry for the word all, two of which are labelled obsolete. • there are leaves all over the car.
Ben 10 All Aliens! by NickyWindu on DeviantArt
As you'll have read in our news pages, all has not been well of late. The whole number of (used in referring to individuals or particulars, taken collectively): How to use all in a sentence.
• katie's toys were spread out all over the floor.
• she had flour and stuff all over her hands. Like quentin delapierre and his crew, we are all looking in the same direction. • the choir has sung in concerts all over the country. The meaning of all is the whole amount, quantity, or extent of.
The whole of (used in referring to quantity, extent, or duration): See ‘meaning & use’ for definitions, usage, and quotation evidence. The governor mounted a halfhearted campaign for the presidency but didn't. When 'all' refers to a group of people/things as a unified whole, it comes with a singular verb, but when 'all' refers to multiple groups.
You use all to refer to a situation or to life in general.
Putting all of one's available resources into an effort: We use all (of) the (with an article), when we're talking about a specific group of the noun. Discover the shared vision of @sailgpfra and @all for more responsible travel, hospitality, and experiences. Games staking all of one's chips, as in poker.
When we say all (of) the students, we're talking about a specific group of students. All is silent on the island now. Every one (of), or the complete amount or number (of), or the whole (of): • there was a sound of.