[pitzips]

I find the Ikea outlet switches are great repeaters. Always plugged in, easy to move around.

[twisteriffic]

The old SmartThings zigbee outlets are rock solid as well, and also have current monitoring. I used mine both as a repeater and to detect a jammed auger in my cat feeder.

[rootusrootus]

I've also had good luck with the Sonoff outlet switches. I've got several of those around the house doing nothing but being mesh repeaters.

[Toutouxc]

I also have a few of these, mine serve as actual switches though. Sonoff stuff is solid.