Nice, it is always interesting to hear about new apps from the f-droid store. It's pretty challenging to find the good stuff in there between the rest.
Let's see what I could add:

- AdAway: easy system-wide AdBlock via /etc/hosts
- AFWall+: simple iptables-based firewall with per app settings
- Easy xkcd: decent xkcd viewer
- Firefox Focus: minimal webbrowser which reasonably protects your privacy
- Paper: nice icon theme
- Silence: SMS app with encryption capabilities
- StreetComplete: Help OpenStreetMaps by checking and adding infos about your sorrounding area