Awh…why, thank you anon! Well, apart from tumblr I can recommend the following communities oncepodcast.com, fanforum.com (once board) and onceuponatime.wikia.com …at least those are the ones I often sneak in to.
Not sure about other blogs since I don’t know about your preferences in regards of the postings? But if you’d like to follow general ones I can highly recommend these (but warning, most of them are not spoiler-free!)
At least those are the ones I do follow. They’re pretty good. :’) If that’s any helpful for the start?