SSH SOCKS Tunneling
ssh -NfD 9000 user@host
This command will ssh into the host but create a SOCKS proxy on port 9000. You can change this port number to any port you'd like. Once this is connected you can start sending traffic over SOCKS via port 9000.
If you have proxychains installed you can edit /etc/proxychains.conf so that the last line is:
socks5 127.0.0.1 9000
This allows you to launch any command and add proxychains in front of it and it will send TCP traffic across the proxy. For instance, proxychains nmap -sT 192.168.0.0/24 would do a TCP scan of the 192.168.0.0/24 network but send it through to the ssh host.