It still kills me to see everyone using 192.168.1.0/24. IMHO, there is only one reason not to use 10.0.0.0/8 and it's because that can sometimes conflict with the address space commonly used for work VPNs. If that's an issue, an arbitrary /16 from the 172.16 - 172.32 range would be a good bet. I haven't really been using cheap consumer routers with their stock OS in a while (maybe 10 years), but is it still common for them to be stuck on 192.168.x.0/24 for the LAN side? I kinda assumed this was more of a problem from like 10 years ago, but I could be wrong I guess.