Android Applications

Tools

File Managers

MiXplorer XDA Labs

MiX Archive Add-On Google Play

MiX PDF Add-On Google Play

Terminal Tools

TermuxAndroid terminal and Linux environment F-Droid Google Play GitHub

Terminal Emulator F-Droid Google Play GitHub

BusyBoxstripped-down Unix tools in a single executable file Google Play

Logs / Stats

SysLogtool to grab Android system logs Google Play F-Droid GitHub

Logcat Extremelogcat/dmesg reader Google Play XDA

BetterBatteryStatsStatistics of power consumption by apps XDA Google Play GitHub

Misc System Tools

ForceDozeforces Doze mode after turning off screen (Android 6.0+) Google Play GitHub XDA

My Android ToolsEnable/disable components (activities, services, receivers)

SD MaidSystem cleaning tool Google Play GitHub XDA

Internet / SMS / Maps

Web Browser / FTP

Firefox Google Play F-Droid

AndFTPFTP client Google Play

E-Mail and SMS

Aqua Mail Google Play

SilenceEncrypted SMS Google Play F-Droid GitLab

Network Tools

AFWall+iptables based firewall GitHub F-Droid Google Play XDA

Network LogNetwork log monitor Google Play GitHub

Maps / GPS

MAPS.MEOffline OpenStreetMap maps Google Play GitHub F-Droid GitLab

GPS TestApp for testing GPS Google Play

Office

Docs / PDF

Xodo PDF ReaderXodo can read and annotate pdf/docx/pptx Google Play

Alarm Clock

OmniClockAlarm Clock, Stopwatch, Timer Google Play

Organizers

DGT GTD & To-Do ListOrganizer using Getting Things Done methodology Google Play

Simple Calendar GitHub F-Droid Google Play

Dictionaries

ColorDictOffline StarDict-compatible dictionaries can be used Google Play

AnkiDroidApp helping to memorize anything GitHub F-Droid Google Play

Camera / Gallery

HedgeCamOpen source camera app Google Play sourceforge

Simple GalleryOpen source gallery for viewing photos and videos GitHub F-Droid Google Play

Audio / Video

VLCOpen source multimedia player Google Play

Sound RecorderSimple sound recorder F-Droid Google Play GitHub

Keyboard

Hacker's KeyboardKeyboad has layout similar to PC keyboard GitHub F-Droid Google Play

Passwords

Keepass DXPassword manager GitHub F-Droid Google Play

MS Windows Tools

APK Tools

APK-Infodetailed info about an apk file GitHub XDA