Learn English – What does ‘made on’ mean here

The ordinary phrase would be what "dreams are made of", but this is a quotation from Shakespeare.

In The Tempest, Prospero, a sorcerer, says:

We are such stuff
As dreams are made on, and our little life
Is rounded with a sleep.

It means essentially the same as "made of".

Remember that very few native speakers can read Shakespeare without help, and that most poetic usage has unusual and overlaid meanings.