For ad-free version check https://play.google.com/store/apps/details?id=com.komorovg.fontiac.pro
If you do lot of customizations on your phone with widgets, etc. you probably try many different fonts to fit best your setup.
But knowing how they will look isn't as easy as it may seem - changing text, its size and font used in widget often requires many steps, and repeating them for each considered typeface can quickly get tiring.
But here's solution - with Fontiac you can quckly load and preview fonts, use custom phrase for preview, resize it and test on dark and light background.
Both TrueType and OpenType formats are supported and phrases you type can be saved for future use.