OpenHub for GitHub - Fast and concise, open-source GitHub client app.
OctoDroid - Mobile GitHub client for Android.
Nullboard - Minimalist locally-stored kanban board / task list manager.
GitNex - GitNex is a free, open-source Android client for Git repository management tool Gitea.
Brisqi - Offline-first personal Kanban app
ForkHub - GitHub client for Android based on the abandoned official app