In '75 at the Forum, Fleetwood Mac was the middle artist on a 3 act bill that had Little Feat opening (& damned near stealing the show) and the Dave Mason Band headlining. That was the last show I saw Lindsey Buckingham play & sing "Rattlesnake Shake"...also, it was one of the many sets where Stevie backed out of singing "Landslide" at the last minute. Lindsey had already strapped on his acoustic and had sat down , even started the intro...Stevie turned around toward Mick holding her hand over her throat in a "choking" motion & shook her head. Lindsey didn't sound too pleased when he made the public apology for her as he strapped on the usual Stratocaster he played on "Over My Head" back then. Of course, Stevie sang her backgrounds perfectly not only on OMH, but the rest of the set as well.
The band "Mistress", which was co-founded by Dave Walker, opened for them at the Santa Monica Civic Auditorium on Thanksgiving Night 1975, although by the time they played that show, Dave Walker was no longer in the band.
In '76, I saw them at UCSanta Barbara (the show that was filmed...later became the outdoor live portions of the
Rosebud video) Small Wonder & UFO were the opening acts. Small Wonder, from Canada, it was their first of only 3 US gigs ever. (their keyboard player Jimmy Phillips later would join Burton Cummings touring band & still was a member when MY band opened for Burton in '81). And, as for UFO, it was one of the last gigs that lead guitarist Michael Schenker played with the band before going AWOL.
A few months later, Peter Ivers opened for them at the Universal Amphitheatre (later known as the Gibson Theatre, which was just torn down about a month ago or less, to make room for a new Harry Potter ride). I recall seeing Firefall in concert, but have no recollection of where...it might've been as opening act for FMac.
At one of their first shows after
Rumours was released, in San Diego in March '77, hometown boy Stephen Bishop opened the show.
The Sanford-Townsend band (RIP Ed Sanford) opened for them during their August '77 run at the Forum. Another near "show stealing" opening band...they were fantastic! Somebody likened them as "a Southern fried Hall & Oates", but I thought they were more along the lines of Wet Willie or Little Feat..extremely tight band with great vocals.
On the early leg of the
Tusk tour, I saw Danny Douma open for them, he had Todd Sharp in his band at the time...and almost all of Fleetwood Mac appeared (on different songs, however, not ever all at once) on his one & only album
Night Eyes. Then Christopher Cross opened for them during their 2 night stay to close out the tour in Sept '80 at the Hollywood Bowl.
Dave Mason opened for them ("unplugged", just he & Jim Krueger (RIP) on acoustic guitars) at the Forum in '82...the two shows that were filmed & released as the
Mirage video.
As John already mentioned, the Cruzados opened for them on the
Shake The Cage tour in '87. The Cruzados bass player (Tony Marsico) would later be a member of Rick Vito's band around the time of his
Pink & Black album.
When I saw them in '90 on the BTM tour, there was no opening act.
In 1994, at the free concert in Woodley Park in Van Nuys, CA, ex-Byrds founder Roger McGuinn did a solo acoustic set, which due to his incessant banter between EACH SONG almost came off as what we would probably today think was an episode of "Storytellers" on VH1.
Wasn't an opening act at either the 2 shows I saw on
The Dance tour in '97, nor when I saw them in 2003.
Haven't seen them since.