I love ads in music magazines in general – the things you find in old 70s Melody Makers, NMEs, ZigZags, Creems, etc (which I've been poring through the last few years for the glam book)
C.f. Lester Bangs's fantasy of owning a huge tunnelled labyrinth of stacks in which were stored every record that ever existed - which now exists for everyone, it's called Spotify / YouTube/ Internet - my update of that fantasy would pertain to what remains still stubbornly material and un-digitized, which is the bulk of the print-and-paper music press pre circa 1998.
(Although I hear there are moves a-foot to digitize the IPC back pages in toto, which is a good move, and various searches and Googles will dredge up great swathes of things - many years of 1970s Village Voice, for instance, with all the small ads and box ads for concerts etc, as well as the reviews and features).
Yeah, a giant room - a maze of rooms - a building even, a back house - that contained most every music magazine that ever existed (well, Q I could probably do without, and Rolling Stone after 1978 probably), every zine....
It's the ads and the sort of para-cultural filler stuff that is as interesting as the reviews and interviews - where you can glean the smell and feel of the times.
Another thing I like is the way that publications that looked impressive and stylish at the time e.g. the Face in the 80s - look lo-budget and a bit shabby now. You see how thrown together it was, both design wise and editorially. Makes it seem more endearing as a cultural project - the projection of metropolitan cool and suss to the provinces, a fantasy of where-its-at / place-to-be... all done on a shoe-string, in a rush.
But specifically re. rave, I have a shitload of old dance magazines boxed up in storage - Mixmags and Muziks and so forth, but quite a lot of the lo production values zine-ish ones.
Eternity and Dream and similar kind of happy hardcore-ish mags of the mid-90s have really tacky merchandise in them and photos of sweaty ravers that are often unflattering. They seemed like that at the time, though - it's not a drop-off into uncoolness caused by the decades passing.