Wi-Fi range extender suggestions?

[pctech]

Although my Netgear D6400 gives pretty good coverage throughout the house there are a couple of areas where I'd like to boost it.

Any suggestions for which plug type extender is the best? 

[Simon]

Not saying it's the best, but I've been using one of these for some time without any problems:

https://www.amazon.co.uk/dp/B00D84GVN0/ref=cm_sw_r_cp_apa_aFDBAbJAQQ8BD