Orgzly Revived is a community maintained continuation of an Android application for notes and tasks using the Org mode format. It exists because the original stopped being developed and the file format was worth preserving.
The organising idea is that everything is a plain text file with a defined structure, so an outline, a schedule, a priority, and a tag are all conventions inside a document rather than fields in a database. Notebooks live on the device, on removable storage, or on a WebDAV server, and synchronisation is file synchronisation rather than an account with a service. The interface supports collapsing and expanding sub notes, swipe actions for common task operations, and a query language with saved searches, which is where the format shows its strength, since a search across structured plain text can express conditions that a simple list application has no way to represent. Operating offline is the default rather than an option, and because the files are readable without the application, the notes remain usable if the project is abandoned again.
The format has a learning curve and the application does not hide it, so anyone unfamiliar with Org mode is learning a convention as well as an application. In exchange the data outlives the tool, which is a trade worth making for notes intended to last.