A usable free proxy server for Windows users (emphasis on usable!)

Q: What is a *usable* free proxy site that you *know* is usable?
(Emphasis on the two highlighted words above: You know it's usable.)

Aside from marketing tricks to get you to purchase something, and aside
from Tor/Opera (neither of which is a "proxy" per se) ... please respond
only if you happen to *use* the proxy you recommend, where I ask...

Q: What is a usable free proxy site that you *know* is usable?

HINT: You know there's a problem with too much data (most of which is
useless in the end) when there is no "top 5" or "top 10" but where the
number starts at the "top 110 free proxy servers".

Mosts are mere useless lists, just like the "free open nntp servers" lists
are.

So this question has the emphasis on two factors:
You (a) *know* that this proxy server is (b) *usable*.

Thanks (in advance) for helping everyone with your response!

-- -- -- -- -- -- -- -- -- -- --
Before you tell me it's easy to find a good one, you should see what a
search reveals - they are just lists of lists - where nobody has the time
to test them out - so I only ask someone who *already* has a good *usable*
free proxy server to recommend.

http://www.idcloak.com/proxylist/fre...vers-list.html
https://www.proxynova.com/proxy-server-list/country-us/
https://nordvpn.com/free-proxy-list/
http://www.publicproxyservers.com
http://www.proxy4free.com/list/webproxy1.html
https://www.alltechbuzz.net/top-best...-servers-2016/
http://www.proxy4free.com