Print all ASCII alphanumeric characters without using them
Octave, 52 46 40 bytes

['['-('"':'+'),'{'-(_='!':':'),_+'@','']


This evaluates to

9876543210ZYXWVUTSRQPONMLKJIHGFEDCBAabcdefghijklmnopqrstuvwxyz


Explanation

Here we are using the fact that characters are implicitly converted to integers when arithmetic operations like +- or the range function : are applied. When concatenated with an empty string ([...,'']), the numbers again are converted to characters.

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