Linx 8
I got one of these for my kid for Christmas. It's a neat little tablet considering it cost me £80. I'm somewhat mystified that I haven't seen an "update to Windows 10" icon on it though. I thought every Windows 7/8/8.1 device was eligible but nothing has shown up so far.
The device itself runs 32-bit Windows but since Windows 10 comes in a 32-bit version I would have thought it was still eligible.