I am making a necro pet build, but I am not sure which stats affect pets (skeleton mage to be specific). Do we have a list of which stats works on pet? I got conflicting information regarding attack speed, online planner said ias does not affect skeleton mage damage, but other forum said it does.

you're right, sometimes it affects it, sometimes it doesn't, it's better to look at your specific build and try to see if there is a note that says anything about it. Some pets don't actually count as pets but necro's skeleton mages do. I think you can use tasker and theo for them or attack speed rolls. Check more details on maxroll.gg