Many unknown MAC addresses connected to router

in the "attached devices" section of my router, and only after pressing the refresh button, a long list of MAC addresses and IPs is present, with excerpts of code as the device name. I have had no security issues with any of my accounts. I also suspect my laptop of having a rootkit, I've not attempted to remove it beyond an unsuccessful system wipe a couple of months ago, as there is no important data on the device. I haven't experienced any unexplained redirects or any malicious activity, other than almost constant outgoing connections, I am almost certain it's just part of a botnet. I plan on building a new PC soon and I just want to get it off my network before doing that. Any help would be appreciated, thanks.