There is an option in STSADM command line to find out the list of stsadm commands related to feature or solution or contentdb etc. Its something like, for example you want to find out what are the stsamd commands used for features...like activatefeature, installfeature etc....
Go to the path where you can run the stsadm command...i.e. in the BIN folder.
stsadm | find "feature"
You will get all the stsadm commands related to feature.... as shown in the screenshot below.