Exchange Rate Widget is a free software for Android, belonging to the category 'Finance'.
I defy you to show me a better looking calendar widget than Month. The material design-style calendar themes (even the free ones) are so gorgeous you'll want...
Battery Widget is a free program for Android, belonging to the category 'Utilities & Tools'.
SLT Zen - Widget Icon Pack is a free software for Android, that makes part of the category 'Personalization'.