What are some examples of a buffer?

Hint: A buffer is an aqueous solution that consists of a mixture of a weak acid and its salt (acid buffer) or a weak base with its salt (basic buffer). Its pH changes very little when a small amount of strong acid or base is added to it and is thus to prevent a solution’s pH change.

Complete answer: Solutions with the stable concentration of hydrogen ions and thus typically with no change in pH which is almost independent of dilution and which change very little with small additions of a strong acid or alkali are called buffer solutions.
simply it can be defined as a solution that prevents any pH change when a small amount of a strong acid or strong base is applied to it is called a buffer solution. Both buffers have acidity and alkalinity balance.
There are three types of buffer, namely
Acidic buffer, Basic buffer, Neutral buffer.
Let us see some examples for each of the following.
Examples:
Acidic buffer – a buffer solution that contains large quantities of a weak acid and its salt with a strong base.
Acetic acid (\[C{H_3}COOH\]) and sodium acetate (\[C{H_3}COONa\])
Basic buffer – a buffer solution that contains large quantities of weak base and its salt with a strong acid.
Ammonium hydroxide (\[N{H_4}OH\]) and ammonium chloride (\[N{H_4}Cl\])
Neutral buffer – a buffer solution prepared by mixing weak acid and weak base.
Acetic acid (\[C{H_3}COOH\]) and ammonium hydroxide (\[N{H_4}OH\]).
So, these are some examples for buffer solutions.

Note:
The natural buffer found in the living systems are;
Bicarbonate buffer – the maintenance of blood pH is regulated via the bicarbonate buffer.
Phosphate buffer – this also acts similar to bicarbonate buffer but has a stronger action.
There are also protein buffers and haemoglobin buffers.