another fan in ur pc case
Noctua NH-D15 if that doesn't fit then NH-U14S if still no fit then NH-U12S.
what case you got?
be quiet! Pure Rock - cheap
Cooler Master Hyper 212 EVO - cheap
Cryorig H5 Universal - medium
Cryorig H7 Universal - medium
Cryorig R1 Ultimate
noctua nh-d14 & 15
Arctic freezer, cooler master and noctua are all good brands. If you do overclock I wouldn't suggest you go for something cheap so don't go for an entry level cooler. Also remember to check the height of the cooler, it must fit into your case!
I've got Thermaltake Water 3.0 with i7 6700k and never had heating problems. Doing video editing on this pc and the processor is handling pretty good.
a cheap air cooler that performs pretty much identical to noctua nh-d15 is scythe fuma.
if ur not heavily oc'ing any good quality 120mm tower cooler should do it... try to read reviews on which have good installation mechanisms etc... hyper 212 evo and other CM tower coolers are usually the sort of standard where people measure price/performance :()