(colloquial) Used to indicate that one aspect of an otherwise bad situation is good. / (colloquial) Used to indicate approval, surprise, &c.

That is the end; there is no more; that's it; that's all

(informal) That's a funny joke (often said to indicate that what has just been said is laughably unbelievable.)

(UK, dated, informal) and that's that

Synonym of that tears it

(UK, informal)

a statement to emphasise the reason or explanation just given

Archaic form of that's the ticket (“that is just right, or exactly what is needed”).

Alternative form of that's what I call

(emphatic) Used to express that the thing in question is an ideal example.