Sinkin Sans by K-Type
Sinkin Sans is a neo-grotesque with good legibility. It includes 18 styles: 9 weights (100 Thin, 200 X Light, 300 Light, 400 Regular, 500 Medium, 600 Semi Bold, 700 Bold, 800 Black, 900 X Black), plus matching italics.
All 18 styles are completely free for personal and commercial use, licensed under Apache version 2.0.
OTF, WOFF, WOFF2
Apache License → Licenses explained