Hell yes there is, and you're already sniffing down the right trail. Writers absolutely have hangouts—but the trick is: they’re rarely labeled “for writers.” They’re usually disguised as:
These are active and alive:
#writeblr – general writing community#poetryblr – poetry-specific#flash fiction – bite-sized story folks#original writing#character development#worldbuilding (this one’s wild and visual)#tumblr fiction – people serialize stories like blog-post zines#mythiccore or #mythpunk – for your style especially#wip – work-in-progress posts, where writers share snippets#web serial or #interactive fiction – where story meets format