We found out about ‘suckers’ lists’ after a scam involving an elderly neighbour - she was conned out of over £100k - all in ‘payments for tax’ on a £1m ‘lottery win’.
These lists are evidently complied and passed/sold on, from any likely source.
In our neighbour’s case I am quite convinced it was because she was addicted to those Wordsearch ‘competitions’, where you so conveniently phone in all your details at ££££ per minute.
It was all done over the phone, she had no internet.
If you have any relative who does these regularly, especially if they’re also at all naive/over-trusting, do please be aware!