I use this one:

/tar [noexists, nodead, harm]; pettarget
/cast Hunter's Mark
/stopcasting
/cast Mend Pet
/petattack
/script UIErrorsFrame:Clear()

Someone correct me if I am wrong, but I believe what it does is pickup a target in front of me if I don't have one, or take the pet targets, casts hunter's mark on it, throws a mend pet (helpful when solo and hitting a sequence of targets), and sends the pet in to attack...