Easy xkcd is a free software xkcd and what if? viewer for android devices.
You can share and favorite xkcd comics and what if? articles, and also view the explain xkcd explanation of every comic.
It supports viewing the alt text by long pressing the comic. You can also view a random comic by pressing the random icon in the bottom right corner. You can search for a comic with its number or title as well.

Pros:

1. Clean look with material design.
2. Night theme included.
3. Adding a comic to favorites saves it on the device and it can be viewed offline as well.

Cons:

1. Big download and binary size (11 MB) given its feature set. This is not much of an issue but I feel it could be cut down.

Slide for reddit is an open source, modern application for Android for accessing reddit. In my opinion it is the best reddit app available and nicer than the other reddit apps available such as reddit is fun, redreader and relay.

Pros

• Modern material deign UI
• Offline viewing
• Customizable UI
• Open Source
• Rapidly improving feature set

Cons

• None that I can think of