F-Droid is an installable catalogue of FOSS (Free and Open Source Software) applications for the Android platform.
Lightweight YouTube frontend that’s supposed to be used without the proprietary YouTube-API or any of Google’s (proprietary) Play Services. NewPipe only parses the YouTube website in order to gain the information it needs.
AdAway (requires root)
An ad blocker that uses the hosts file. The hosts file contains a list of mappings between hostnames and IP addresses. When an app requests an ad, that request is directed to 127.0.0.1 which does nothing. There are options to run a web server to respond to blocked hostnames and to direct requests to the IP address of your choosing. You can download hosts files from the app but it is possible to use your own and to add certain sites to the white- and black-lists.
Requires root! The hosts files is located in /system which is normally read-only. However, you can push your own hosts file without the need of external applications via Android Debug Bridge (ABD). This also requires root.
Yalp Store lets you download apps directly from Google Play Store as apk files. It can search for updates of installed apps and lets you search for other apps. Yalp saves downloaded apks to your default download folder. Other features include browsing categories, viewing and leaving reviews, black/whitelisting apps for updates, filtering apps by being free/paid and containing/not containing ads.
Orbot is a free proxy app that empowers other apps to use the internet more securely. Orbot uses Tor to encrypt your Internet traffic and then hides it by bouncing through a series of computers around the world. Tor is free software and an open network that helps you defend against a form of network surveillance that threatens personal freedom and privacy, confidential business activities and relationships, and state security known as traffic analysis. Orbot creates a truly private mobile internet connection.
Xposed (requires root)
You can extend Android functionality with Xposed, using so-called modules.
xPrivacyLua (Xposed module, requires root)
Really simple to use privacy manager for Android 6.0 Marshmallow and later (successor of XPrivacy).
Revoking Android permissions from apps often let apps crash or malfunction. XPrivacyLua solves this by feeding apps fake data instead of real data.
With xPrivacyLua you can protect your privacy.
YouTube Vanced (Non-root / Root / Magisk)
YouTube Vanced is a new modded version of YouTube which contains a lot of features like ad blocking, background playback and many more.