Monoalphabetic Substitution:
Quipqiup
https://quipqiup.com/ auto solverBoxentriq
https://www.boxentriq.com/code-breaking/cryptogram auto solverGuballa
https://www.guballa.de/substitution-solver auto solver in English, German, Spanish, French, Dutch & PortuguesePolyalphabetic substitution:
Boxentriq
https://www.boxentriq.com/code-breaking/vigenere-cipher (best vigenere with no key solver)Guballa
https://www.guballa.de/vigenere-solver (autokey vigenére & beaufort decoder in English, German, Spanish, French, Dutch & Portuguese)F00l
https://f00l.de/hacking/vigenere.php (vigenére key length calculator)Caesar:
Regular Caesar
https://a4x.me/tools/text/ (easy atbash/reverse/rot testing)Caesar with numbers as well
http://theblob.org/rot.cgiCaesar with other language alphabets
https://planetcalc.com/1434/ (alphabets for English, French Portuguese, Russian & Spanish)Cipher Identifiers:
dCode Cipher Identifier
https://www.dcode.fr/cipher-identifier(best one)bionsgadgets Cipher Identifier
https://bionsgadgets.appspot.com/gadget_forms/refscore_extended.htmlBoxentriq Cipher Identifier
https://www.boxentriq.com/code-breaking/cipher-identifierbase64 Looking Text:
Dumpster Diver (random b64 looking text brute forcer)
https://corgi.rip/diveAesencryption.net (AES)
https://aesencryption.net/Stupid Base64 aka SB64 (AES)
https://www.online-toolz.com/tools/text-encryption-decryption.php/Codebautify (Arcfour)
https://codebeautify.org/encrypt-decryptencipher.it (AES PGP)
https://encipher.it/Paranoiaworks (AES EAX)
https://pteo.paranoiaworks.mobi/samltool (XML)
https://www.samltool.com/decode.phpaesdecryption (AES)
https://decipher.wiki/aes-decryptionsamltool (base64 + decompression)
https://www.samltool.com/decode.phpgAAAAA AES, aka Ferdecode
https://asecuritysite.com/encryption/ferdecodebrowserling (salted openssl)
https://www.browserling.com/tools/aes-encryptDevglan (AES)
https://www.devglan.com/online-tools/text-encryption-decryptioninvertexto (AES)
https://www.invertexto.com/texto-criptografadoencode-decode (AES)
https://encode-decode.com/aes256-encrypt-online/anycript (AES)
https://anycript.com/cryptoi (AES presented in emojis)
https://web.archive.org/web/20220915201921/https://cryptoji.com/Others:
n-gram transcription
https://www.dcode.fr/alphabetic-transcription (transcribes text in any group length)View non-printables
https://www.soscisurvey.de/tools/view-chars.phpWord completer
https://www.onelook.com/ (search ??i???n??e and get CHIMPANZEE for example)Link identifier
https://a4x.me/tools/link/ (oHg5SJYRHA0 for example)Byte shift
https://cyber.meme.tips/xlate/shifts.html (View all byte shifts and all constant XOR’s)Casing inverter
https://www.browserling.com/tools/text-invert-caseEnglish language frequencies 1
https://www3.nd.edu/~busiforc/handouts/cryptography/cryptography%20hints.htmlEnglish language frequencies 2
https://norvig.com/mayzner.htmlEsolangs decoder
https://tio.run/#Large number converter
https://www.mobilefish.com/services/big_number/big_number.php (Binary, hex, decimal & base64 conversion)invisible characters in text decoder
https://330k.github.io/misc_tools/unicode_steganography.htmlDork search tool
https://www.dorksearch.com/Osint framework
https://osintframework.com/