Open Camera - Open Camera is an open-source camera app for Android phones and tablets.
Yandex.Images - search for images on the internet, search by image
Secure Camera - Modern camera app focused on privacy and security with QR & barcode scanning.
TinEye - Reverse Image Search to help find an image's source, duplicates or altered versions.
PhotonCamera - Android Camera that uses enhanced image processing.
SauceNAO - SauceNAO is a reverse image search engine.