The Letter A without A

Python 2, 14 bytes

print`3<3`[~3]

The expression 3<3 gives the Boolean False, and the backticks give its string representation 'False'. From here, it remains to extract the letter a. Python is 0-indexed, so the a is at index 1, which is a banned character. It can be expressed as 3-2, but there's a shorter way. Python allows indexing from the back, with index -1 for the last entry, -2 for the one before it, and so on. We want index -4, but 4 is also a banned number. But, we can express it as ~3 using the bit-complement ~, which gives -n-1 for ~n.

Pluso, 1 byte

o

Pluso Esolangs Page.

Pluso contains a single accumulator, that starts with the value 1. It uses two commands, p which increments the accumulator (mod 27), and o which prints the current value as an uppercase ASCII character, A-Z or space (where 1-26 represents A-Z respectively, and 0 represents space).

As the accumulator starts at 1, the command o with no prior p will output A.

Pyth, 2 bytes

hG

Test it in the Pyth Compiler.

How it works

 G  Yield the lowercase alphabet.
h   Extract the first character.