Open Camera is a fully featured and completely free Camera app.

Features:

• Option to auto-stabilize so your pictures are perfectly level no matter what (see example image).
• Expose your camera's functionality: support for scene modes, color effects, white balance, ISO, exposure compensation/lock, selfie with "screen flash", HD video and more.
• Handy remote controls: timer (with optional voice countdown), auto-repeat mode (with configurable delay).
• Option to take photo remotely by making a noise, or by voice command "cheese".
• Configurable volume keys and user interface.
• Upside-down preview option for use with attachable lenses.
• Overlay a choice of grids and crop guides.
• Optional GPS location tagging (geotagging) of photos and videos; for photos this includes compass direction (GPSImgDirection, GPSImgDirectionRef).
• Apply date and timestamp, location coordinates, and custom text to photos; store date/time and location as video subtitles (.SRT).
• Panorama, including for front camera.
• Support for HDR (with auto-alignment and ghost removal) and Exposure Bracketing.
• Support for Camera2 API: manual controls (with optional focus assist); burst mode; RAW (DNG) files; slow motion video.
• Noise reduction (including low light night mode) and Dynamic range optimisation modes for better quality photos.
• Options for on-screen histogram, zebra stripes, focus peaking.
• Focus bracketing mode.
• Completely free, and no ads in the app (I only run ads on the website). Open Source.

(Some features may not be available on all devices, as they may depend on hardware or camera features, the Android version, etc.)

Note that it's not possible for me to test Open Camera on every Android device out there, so please test before using Open Camera to photo/video your wedding etc :)