I am new to bash script. I need help in parsing a text file (say sample.txt) which contains the data like below

*AR   eth0      ethernet0
*A    eth1      ethernet1
      eth2      ethernet3
                ethernet4
*A     eth5      ethernet5
      T  E S T  ethernet6

I want the output like below

eth0
eth1
ethernet3

eth5
T  E S T

I have used below command, but it did not worked

sed 's/^ {1,}/SPACE_PLACEHOLDER/g' sample.txt | awk '{print $2}' | sed 's/SPACE_PLACEHOLDER/ /g'