Let's go back for a moment to 1984. Coming off a terrible 60-102 season, the Mariners have made numerous trades in an effort to avoid that terrible outcome again. Legends such as Bob Kearney, Dave Beard, Barry Bonnell, Jack Perconte, and Gorman Thomas would help the club to a significantly better 74-88, good for 6th in the division (out of seven). Outside the world of baseball, the year would start with the breakup of AT&T, bringing about the seven 'baby bells.' What do these things have to do with one another? Very little.
Fast forward now to 1986. Every year the team would issue a set of postcards with player photos on them. This however would be the first year that these had a sponsor listed on them. And that sponsor was Pacific Northwest Bell. That is the only thing these two topics have to do with one another. However this did for the first time provide an actual identifying mark to hopefully distinguish what year each one was released in. You see from 1977-1983, no such markers existed. You can pretty much only discern one year from the next based on slight variations in font or spacing, and of course if a player was on the team in a particular year or not.
But why, might you ask, does any of this matter? Well there aren't a lot of cards to collect from those early Mariners years. As of writing this, I have 1691 total cards from 1977 through 1986, and am missing 249. Almost all of those I'm missing are team-issued postcards. So for the few out there that might collect such things, I wanted to provide a quick visual guide to the four years of Pacific Northwest Bell/US West sponsored postcards so you actually know what is what.
1986 (Upper Left) - Trident Logo, Pacific Northwest Bell, both centered. Some are missing the Mariners logo, but are still from this set.
1987 (Upper Right) - Pac Bell logo in bottom right, US West font is very small
1988 (Lower Left) - Pac Bell logo in bottom right, US West font is similar size
1989 (Lower Right) - Changed to USWest Communications
While none of these, or any other year for that matter, aren't easy to find, it seems that 1987 is the hardest. In fact according to tcdb.com, it doesn't even exist. Once I have a better idea of a checklist, I will have that remedied. As it stands, I've only found three. If you dive into these or other non-sponsored years, the earlier ones can mostly be found, both checklisted and many with images, on the aforementioned tcdb.com.