@TP-Link_Deco 

the problem I have is with a netatmo base station that keeps disconnecting from the deco mesh. From time to time it will appear and I can pick up the MAC address during that limited time frame. In a nutshell I'm thinking that moving from one satellite to another could cause the problem of disconnection.
 

another use case could be a device that is offline for now or in sleep deep mode and reappears from time to time on a schedule.

the moment you have a list of MAC addresses Let's just post all of them instead. You have the list on the summary page online and offline so why not use it. It's just probably a filter on the On tag.

Just wanted to chime in on this.   I have several family members that come over from time to time and bring their phones to connect to my network.  With my home automation hub, I can utilize their ip addresses to indicate their presence in the home network and limit some access.  While their devices show up as offline, I would like to be able to add them into the network instead of trying to remember to do it when they are in the house.   They all know I am doing this, but being able to manually add the reservation is something every router I've had in the past has been able to do based on mac address.  Even just having that ability on the web portal would be sufficient.  That way you wouldn't have to change the app at all.

I would also like the ability to assign a static IP based on a MAC address.  I had the ability while using my previous router with the DDWRT firmware.

Thank you.

@Stefou 

I also would like this feature.  It would be useful to be able to configure IOT devices without having them connected to the network yet. 

Thanks.