The first two MAC address don't return any results when looked up. Double check they're 100% correct, especially the first 6 characters.
The last MAC address is a Roku.
This is my sytem log.. hopefully you can read the mac addresses that are connecting and disconnecting. This is just from tonight when I left my house with our kids and my ex was left home.. Just odd because some of the devices only connect when he is here but others connect and disconnect throughout the day while he is at work..
One thing to keep in mind. Seeing things connect and disconnect frequently is NORMAL. Especially for most modern devices including those that are hard wired. It's part of the power saving features most devices have. If certain devices only connect when your ex is there, that could be just a cell phone or a laptop for example. Snooping on network traffic is nearly impossible unless you are using unencrypted connections, which are quite rare these days. If you're really worried, use a VPN.
If you just have the Telus router and don't have one of the Telus Boost units connected, then wired devices will show as ethernet in the system log and wireless ones will appear as 802.11 clients. At least going by the system log on my T3200.
From the few I can see in that screenshot you posted:
I can see in the tabs on your browser that you've tried searching a few others. If you have other MAC addresses, you can use a few different sites to look them up. Some manufacturer names you may not recognize and they can be perfectly safe still. The most you'll get is the manufacturer name of the network chip. The sites are also only as good as their databases too. If they are older and out of date, the MAC address may not return any manufacturer information as well.
The mac address that you said would have been a PC or something that is Intel Corp ... We actually do not have any laptops in our home.. only 2 ps4's and i already checked the macs of both of them and no match... He was the only one with a laptop but has taken it to his parents but he is still over here daily after work for a few hours.. and when shows up... usually 3 devices connect and when i asked him if he has anything on the wifi other than his cell he said no... but he has a past of doing weird stuff like this.. as I was told from Telus a couple years ago that there was a wireless network adapter or something connecting to the network but it had its own server or something ( lol im not techy at all sorry if it doesnt make sense) but he said that devices that were connected to my wifi were disconnecting and connecting to the wireless network adaptor. He also said it had to be in the house somewhere but would have to be within a 1 block radius from the house to connect.. or he said it must be hidden.
Does this make any sense lol?
Intel is merely the manufacturer of the networking hardware itself. Intel doesn't make computers under their own name besides the NUC. Any other computer or device manufacturer could choose to use an Intel chipset for their networking. While you may not have laptops, desktop PCs frequently do have Intel chipsets.
Are you sure you were talking to a real Telus rep? None of that makes sense. Wifi definitely has less than a 1 block range. You'll be lucky to even get reception in most cases when you're outside your home or yard. Having to use the wireless boosters is proof of that. Hidden wifi networks can be easily found. Any device connecting to the Telus router will have its MAC appear in the log.
Not all MAC addresses are going to show up in a search. It depends if the device is from a manufacturer that registered the first six characters of the MAC address or not. There are also some other devices where people can manually change the MAC address. Another thing to be aware of is that many devices have more than one MAC address. One for wireless, one for wired and in some cases more additional ones depending on the hardware.
If you are really worried, change ALL of your wireless network names and passwords. It will be a headache at first but it would make it harder for unknown devices to connect. As long as you are the only person with the password, you can limit who or what device has access. For your ex, you could even set up the guest wifi with a separate password and isolate it so anyone on the guest wifi cannot access anything on the rest of your network.
So I took your advice and I blocked the mac addresses that i couldnt match with any devices in my house. But since then, around midnight last night a new mac connected to the wifi and I did try to search it but couldn't figure it out... maybe you could help me find out what kind of device it would belong to?
And there was nothing that would have connected at that time that would have been one of my devices or my kids.. as we were all in bed asleep. Just creeping me out.. And we do have a wifi booster that my ex set-up before he moved out a month ago which is connected via ethernet.. Just creepy