CTB-Locker (Curve-Tor-Bitcoin Locker) belongs to the family of ransomware viruses. It is also known as Critroni ransomware. This is also crypto-virus and it uses RSA 2048 encryption to encrypt sensitive files and folders. Usually CTB-Locker encrypts user documents, photos, music and other types of personal information. After this it asks for a ransom in bitcoins (0.3 or $120). CTB-Locker modifies file names and extensions of encrypted files. All affected files get .ctb or .ctb2 extension.
TeslaCrypt is virus that belongs to ransomware category of crypto-viruses. TeslaCrypt encrypts important documents, images, presentations using AES encryption. Then it demands a payment (ransom) for decryption key that will allow user to restore the files. One of the "features" of TeslaCrypt is that it also encrypts game files of 40+ popular games like Dota, Minecraft, World of Warcraft etc.
Locky virus is ransomware threat that encrypts documents, music, video and other information on victims computer using AES encryption. This virus can also encrypt folders on unmapped network shares. It modifies affected files extensions to .locky. After this it demands ransom in bitcoins (0.5 - 2 BTC or approximately $200 - $800) for decryption services. There is no known guaranteed way to decrypt files infected by Locky virus and that is why this blackmail virus is considered very harmful.