That leaves UCEPROTECTL3

Is anyone still using them?

I see a lot of spam coming from sendgrid, so I wonder how long they can continue operating that way until they get blocked completely by one of the larger mailbox providers.

Isn’t that mainly just torrent trackers that publish your IP address and then the ISP gets a request for who was using that particular IP address. I don’t think an ISP would itself be interested in detecting whether their customers download illegal content - there is no business case for them to do that.

Also the location of known Wifi networks.

There is also lowendspirit, but in both cases you have to be very careful what you buy - not everything that is advertised there will work as advertised or will work long-term

where they will double your monthly data limit for free when you comment your order number.

where they use you to spam the forum thread (for giving away something rarely anyone has any use for)

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“secure alternative”? Others are not secure?