Before it became a jazz station, 105.9 used to be WCXR, a classic rock station (the first one I remember using the term "classic rock"). It replaced KIX-106, a country station. Edited to add: They started the classic rock format on 26 January 1986, two days before the Challenger accident, and became a "smooth jazz" station on 30 September 1994. The latter date was about nine months after 94.7 switched from being "lite rock, less talk" to a classic rock station.
100.3 used to be an oldies station.
106.7 was B-106 back in the 1980s. I recall it was a popular station, but I didn't listen to it. I do recall their bumper stickers that said "Playing the best new music first!" When they changed formats in 1986 or 1987, they did an all-Beatles weekend and then started using their full call letters, WBMW, before changing to WJFK.
For many years 99.5 was an "easy listening" station with the call letters WGAY. Fill in your own jokes about that. (I heard that station way too often as a kid because my mom listened to it.)