There are a TON of wonderful designers out there to bookmark. Be sure to look into the classically great as well as the contemporary.
Here’s a starter list:
Paul Rand
Stefan Sagmeister
Milton Glaser
Chip Kidd
Michael Bierut
Neville Brody
Paula Scher
Lucille Tenazas
Alan Fletcher
Wolfgang Weingart
Armin Hoffman
Eric Spiekerman
Josef Muller-Brockman
Kyle Cooper
Thanks @JamesKurtz!