Hopefully this list should cover most (if not all) codes:
100: Internal exception/User banned
101: Object lookup fail
102: Object already exists with unique ID
301: Invalid session key
302: User authentication failed
303: Permission denied, user not fully registered, feature not enabled
304: Permission denied for IP
305: Read or modify not allowed for user from session cookie
306: Feature not configured
307: Invalid cross origin request
308: OAuth2 authentication failed
309: Referrer check failed
400: API exception