Freepascal examples using libssh2 (https://github.com/libssh2/) : a ssh client, a sftp lient.
Also have a look at https://github.com/erwan2212/dokan-delphi/tree/master/Samples/Proxy_SFTP : the ability to mount a windows logical drive to a remote sftp.
Various libssh2.dll are provided as well (all tested ok) - these can also be found in older php releases here https://windows.php.net/downloads/pecl/releases/ssh2/ .
Latest libssh2.ll can be found in in php releases here https://windows.php.net/download/ .