Who is good at finding PBNs?

I got some competitor ranking #1 with just measly 40RD. Id say there are only aprox 10 quality links on /. they are aged, and on authority sites.
however, I expect they got more "behind".

if so. is good at sniffing 'round the hidden stuff, please PM me or post some idea besindes smallseotols how to find them..