Probably a Raijintek Tisis or a Phanteks TC14PE, they seem to be the cheapest dual tower coolers and are close to D15 performance wise.best air cooler for a 1700x in terms of value for money? the cheaper the better however i will pay say a few quid more if warranted. for example i'm currently using a hyper 212X (£25) on a i5 7600K as it's a beast for the money. is there anything as good as that for AM4?
You can find some performance numbers here: https://www.anandtech.com/show/9415/top-tier-cpu-air-coolers-9way-roundup-review/12