This highly curated collection feels more "true to life"than most stock sites (photos are often shot in untraditional perspectives). Plus their watermarks are usually unnoticeable and their images are pretty cheap if you have to buy them.
Shutterstock is a great resource with a MILLION different shots of absolutely ANYTHING you put into the search bar. Their prices are pretty affordable too. To save even more on cost, try splitting a 25 images/day monthly subscription with another freelancer!
Pinterest is still one of the best places for inspiration. If you know the right people to follow or just follow a photo's path, you can uncover some unique finds. And by the way, I have tons (and I mean TONS) of Pinterest boards to inspire and delight you for hours and hours. :) ur welcome!
It might be an obvious answer at this point but sometimes the obvious is easily forgotten. Instagram is photography central. Start here for some great true-to-life photography AND a lot of professional photography at the input of a #.
Fashion / Lifestyle Bloggers
Usually I find great fashion/lifestyle bloggers through Pinterest links or Google searches. What's really great about imagery found this way is that there are a GAZILLION lifestyle bloggers out there right now taking a GAZILLION photos every day. You can often find amazing images for really specific image searches.
If you want honest, real portrayals of people from all walks of life, Humans of New York can't be beat. No matter where or who they are, Brandon Stanton is amazing at capturing the essence of the person and their environment. I don't use this resource a ton because the format of retrieving them isn't super easy, but it is great when I can't find someone "real" enough on other sites.
In my opinion, Getty is best for small-res screen captures. Its stock photography is, of course, gorgeous but they're like that hot girl that knows she's hot, she's fun to look at but do you really want to date someone with that level of maintenance?? Getty-girl, you're too damn expensive, no one wants to pay for that shit.
Tumblr can be a great resource, but it is one of my last go-tos, just because it's so random and you can't search easily for the images you need. BUT! When you DO find a good Tumblr account, type in their web addy with "/archive" at the end, and you'll see all their goods at once. Make sure you pin it so you can find it again in the future! And don't get side-tracked by all the memes :)
This is my last resort. There's tons of imagery to wade through, but much of it will be total crap or watermarked and probably not what you were hoping for. The unique (and great) photos might be there, but they will be few and far between.