All MLB Logos as Red Cs (explanation in comments) : r/baseball
UNOFFICiAL ATHLETIC
Sports Logo Spot: Seattle Mariners
Mariners have the perfect reason to change their uniforms now - Seattle Sports
Seattle Mariners rumor: Total rebrand with new logos and uniforms in 2021
Seattle Mariners unveil City Connect uniforms - ESPN
Seattle Mariners Rebrand on Behance
UNOFFICiAL ATHLETIC
Seattle Mariners Rebrand - Concepts - Chris Creamer's Sports Logos Community - CCSLC - SportsLogos.Net Forums
Major League Baseball / Useful Notes - TV Tropes
UNOFFICiAL ATHLETIC Toronto Blue Jays Home and Away Uniforms Rebrand