far-ssh and far-scp, when you need to access or copy files through a server acting as a proxy.

far-scp.fish

function far-scp
    if count $argv > /dev/null
      echo Connecting through $argv[1]
      echo Source: $argv[2]
      echo Dest:   $argv[3]
      scp -oProxyJump=$argv[1] $argv[2] $argv[3]
    else
      echo " usage: far-scp [proxy-addr] [src] [dst]"
    end
end

far-ssh.fish

function far-ssh
    if count $argv > /dev/null
      echo Connecting to $argv[2] through $argv[1]
      ssh -t $argv[1] ssh $argv[2]
    else
      echo " usage: far-ssh [proxy-ssh] [target-ssh]"
    end
end