Blocksy - A lightningfast, innovative and supercharged WordPress theme
WordPress Theme Search - What WordPress Theme Is That?
GPLDL - 1066 GPL-licensed WordPress themes & plugins for free
Readable WordPress Theme - The first Medium.com like WP theme with great readability
Neve - With an intuitive header builder, 100+ pre-designed sites, a LOT of WooCoomerce modules, global colors & a way to share saved templates across sites, Neve is a great choice for beginners & freelancers/agency owners alike.
Litmaps - Search scientific literature with interactive citations map