Hay otras posibilidades de describir un gran número de una cosa, aunque algunas de estas expresiones forman parte del lenguaje coloquial.

Resumen
lenguaje estandard singular (incontable) plural (contable)
a great deal of a good many
a good deal of a great many
a small amount of a great number of
a large quantity of a good number of
a large number of
lenguaje coloquial
a lot of a lot of
lots of lots of
plenty of plenty of
Ejemplos
I found a great deal of sand in my kitchen; I do not understand how it got there.
She has a great many children to feed.
There is a good deal of work to do, before we are ready for the presentation.
There are a great many open questions to answer.
A small amount of food was left for him.
A great number of mistakes were to be found in the first version.
In the sea, there is a large quantity of water.
In the lake, there are a good number of fish.
A large number of photos were taken.
A lot of time has passed.
A lot of fans wait outside.
Lots of milk went sour last week.
Lots of apples can be found in our garden.
There is plenty of air in the room; still I cannot breath.
There are plenty of women waiting for Mr. Right.