As a lemmy client, I would add Eternity (APGL-3.0).

For latex documents I would highly recommend Overleaf (APGL-3.0). You can selfhost it on an old PC or raspberry pi and have crossplatform access on all your devices

A better alternative to F-Droid would be Neo Store (GPL-3.0) which has a more modern design and is less broken in general.

For apps that are only available as github releases (e.g. hypeBard) I would recommend obtainium (GPL-3.0) which automates the update process.

My personal preference for calculator apps is NCalcLibre (GPL-3.0) which has a slightly different set of features than your suggestion but has a more structured UI imo.

Text Tools Pro (Apache-2.0) is another awesome tool that can improve your typing experience dramatically.

If you have a degoogled device you might want to install FMD (GPL-3.0) in case you lose it.

For rooted devices, I would also add BCR (GPL-3.0) + BCR-GUI (GPL-3.0) to keep a record of important calls.

Another app that is especially useful on rooted devices is AdAway (GPL-3.0) which is a system-wide ad blocker that doesn’t require any resources.