Could be an interesting task to look up in DdmrDdmr's Merit dashboard. From what I know, LFC_Bitcoin is actively distributing Merit in our Gambling section but it's not enough of course. From all sections, Gambling seems to be the biggest one, overtaking Altcoin Discussion and Bitcoin Discussion after especially in Bitcointslk's Altcoin, activity declined due to bankrupt shitcoins. 
And we have so many different Gambling topics, it's close impossible to impossible for even 5 Merit sources to notice every post. Of course, Gambling section is 95%+ of posts not deserving any Merit, too.