Monoalphabetic Substitution Ciphers
...A list of Monoalphabetic Substitution ciphers

Atbash Cipher
The Atbash cipher is a substitution cipher with a specific key where the letters of the alphabet are reversed. I.e. all As are replaced with Zs, all Bs are replaced with Ys, and so on.

ROT13 Cipher
The ROT13 cipher is not really a cipher, more just a way to obscure information temporarily. It is often used to hide e.g. movie spoilers.

Caesar Cipher
The caesar cipher (a.k.a the shift cipher, Caesar's Code or Caesar Shift) is one of the earliest known and simplest ciphers.

Affine Cipher
A type of simple substitution cipher, very easy to crack.

Baconian Cipher
The Baconian cipher is a 'biliteral' cipher, i.e. it employs only 2 characters. It is a substitution cipher.

Polybius Square Cipher
The Polybius Square is essentially identical to the simple substitution cipher, except that each plaintext character is enciphered as 2 ciphertext characters.

Simple Substitution Cipher
A simple cipher used by governments for hundreds of years. Code is provided for encryption, decryption and cryptanalysis.

Codes and Nomenclators Cipher
Nomenclators are a mix between substitution ciphers and Codes, used extensively during the middle ages. Codes in various forms were used up until fairly recently.