Examples of websites using
Plain
('Plain' is a sans-serif font designed by François Rappo and released by Optimo in 2013. The family consists of 11 individual styles, including regular, italic, and bold weights)
with
Trio Grotesk
(Trio Grotesk is a sans-serif font designed by Bold Monday. The family consists of 72 styles, including regular, condensed, and extended widths, each available in 6 weights with matching italics)