just make sure they are not requiring kyc at any point of your active betting. because some casinos and bookies won't ask kyc when you deposit but upon withdrawal, they will require you to submit kyc. so always check their ToS before it is too late.
but old sites like freebitco, we all know they don't require one. and it is reputable site known to this forum. so if you do want to play anonymously without worrying about them asking your kyc, check the reputable ones first.
for experienced gamblers I'm sure they understand everything about casinos without KYC and those asking for KYC, but for novice gamblers they very rarely understand this problem so many cases of gamblers complain of being refused when withdrawing funds on the grounds that KYC was refused because it was in a prohibited country according to the provisions Casino ToS.
so it is very important for all professional and novice gamblers who want to gamble on online sites to always pay attention to the ToS in the FAQ before making a deposit or making a bet to avoid similar incidents.