SB cold called 3-bet OOP! Is it like AK, TT-QQ?
Anyway we flopped a monster. He checked. Here I would like to think more general about c-betting. With top set we are blocking top pair a lot. I tend to bet here some draw heavy boards. Here not much of hands that will continue. Some FD, may be PP. What do you thing about betting top set here and in general? I decided to check to keep him in a pot.
Turn is A. He checked and now we definately are going for some value.
River is diamond 7. Probably it is a good card for a buff. But his sizing is almost 1.4x pot! Dont see him having some 58 or 35 type of hands. I dont think he would bet that sizing with dopers/sets. From mine point of view he has flush or air range. What do you think?

PokerStars - $0.25 NL (6 max) - Holdem - 6 players
Hand converted by PokerTracker 4

SB: 102.04 BB (VPIP: 31.91, PFR: 17.02, 3Bet Preflop: 0.00, Hands: 49)
BB: 106 BB (VPIP: 28.93, PFR: 22.64, 3Bet Preflop: 7.69, Hands: 162)
UTG: 121.92 BB (VPIP: 20.00, PFR: 13.33, 3Bet Preflop: 12.50, Hands: 16)
MP: 44.36 BB (VPIP: 33.33, PFR: 0.00, 3Bet Preflop: 0.00, Hands: 3)
Hero (CO): 100 BB
BTN: 100 BB (VPIP: 0.00, PFR: 0.00, 3Bet Preflop: 0.00, Hands: 2)

SB posts SB 0.4 BB, BB posts BB 1 BB

Pre Flop: (pot: 1.4 BB) Hero has K K

fold, MP raises to 3 BB, Hero raises to 9 BB, fold, SB calls 8.6 BB, fold, fold

Flop: (22 BB, 2 players) 4 6 K
SB checks, Hero checks

Turn: (22 BB, 2 players) A
SB checks, Hero bets 10.48 BB, SB calls 10.48 BB

River: (42.96 BB, 2 players) 7
SB bets 59 BB, Hero - ?

Cbet small to get value from pocket pairs and protect from draws. If he completely whiffed you're very likely not getting any value anyway.
I'd close my eyes and station off river just because I think he could be spazzing with two pair or a worse set. There could also be times where he perceives the 7d to be a good bluffing card for him and decides to try and blow you off whatever.

not betting flop is a mistake, i know u block Kx but there are tons of value to get still + its a board you would cbet as a bluff very frequently.

im calling river.