If you're looking for unique, authentic and sometimes imperfect stock photos - tookapic stock has all of that. Unique collection of photos from people running their 365 projects (one-photo-a-day journals). $39/mo or $99/y gives you unlimited access to more than 85.000 photos.
FreePhotos.cc is a free resource where you can find creative commons photos for your website or print projects.
Search for any topic using the search box (e.g. "Dogs", "Flowers", etc.), browse results and download.
Royalty-free Nature Stock Photos. Use them however you want. Created by Adrian Pelletier. Updated daily.