Recalling how close friends or associates used terms to address each other besides their name or nicknames, I remember my parents call them "Kumpadre or Kumpare" (for the male species) and "Kumadre or Kumare" (for the female species). That was in the 1960s. Well, that was for the more elderly or those married and/or with children. The younger generation male then picked up from this, shortening it to "Pare" among their male pals. I don't think the younger women then used "Mare" addressing friends.
Kumpadre, kumpare, kumadre and kumare are monickers (if that's the right term) for those who are godfathers or godmothers for a friends son or daughter. These monickers denote closeness of friendship that made it the reason why Filipinos used the terms for friends. In urban cities, I believe, the terms are still used in short as "pare or mare".
In the 70s, there were many terms used to address friends such as "Utol or 'tol" (meaning brother/sister), "pards" (a corrupted short for partner) and "Bro", often pronounced as "bru" adopted from the military short for brother. This was for the younger generation. The Kumpadre or Kumpare and Kumadre or Kumare were still much used by older people until the mid 1990s. The shorter versions of Pare, Pre or Mare are still used by the middle aged.
Some time in the 80s, the terms "Chong (tsong) and Chang (tsang)" were also used to address friends. It was the short for "Tiyong and Tiyang" that meant uncle and aunt. It was short lived though. In the late 1980s, if I remember right, I heard my teenage son and his friends again address each other as "'tol". Until now, it still seems to be the common reference among friends for the younger generation, something like 40 years old and below.
What it was in our city could be different in other localities, then and now.