Most handy piece of swag is the Meraki USB-A/C to C charging cable.
It has gone straight in my travel bag and works on the HS1 Javelin trains
It also functions on the Stagecoach, which is, alas, not as fast
Unfortunately - there doesn't appear to be any Meraki kit I can charge with it whilst en-route.
The other day when I was juggling pass cards at my London site, I thought that a lanyard would be handy (hint hint).
If I'm honest the best piece of kit that I have received is my Z3C, which is almost perfect, all it requires is an ability to connect to a WAN as the LTE connection is shielded/blocked in the sites I visit . . .
The chutzpah award goes to the Cloud cork board into which are pressed pins representing Meraki devices and software. Completely useless, but I love it.