I don't think they are online as complete flyers, but at least some of the short stories are online:
http://old.shadowrun4.com/fiction/I have the following flyers:
#1001 (pre-publication of SR, 1989, cover: SR1 cover)
* The year is 2050
* After Midnight
* Timeline 1999-2049
* UCAS map
* High Dive
* Humans & The Cycle Of Magic
* Shadowrun Coming in August
* Other Shadowrun Products (Miniatures from Grenadier, The Seattle Sourcebook)
* Hot New Talent in Seattle
#7101 (unknown date, cover: SR1 cover with yellow "update") Mine is a not very good photocopy

* The year is 2050
* Timeline 1999-2049
* Rex Tremendae
* Mercurial
* DNA/DOA
* Shadowrun
* Humans & The Cycle Of Magic
* Coming for Shadowrun (Shadowrun Anthology, Sprawl Sites One, Dream Chipper, Street Samurai Catalog, Paranormal Animals of North America)
#? (1989, cover: DMZ with "1990 update")
* The Year is 2050
* Better to Reign...
* Downtown Militarized Zone
* Humans & The Cycle Of Magic
* Paranormal Animals of North America, The Grimoire, Anarchist's Gide to North America, The Universal Brotherhood
#1002 (unknown date, cover: Ivy&Chrome)
* The World of Shadowrun: The Year is 2050...
* Wyrm Talk
* 1991 Releases (Neo-Anarchists Guide to North Amarica, Ivy & Chrome, Virtual Realities, The London Sourcebook, Native American Nations Volume One, Native Amarican Nations Volume Two, The Rigger Black Book)
* Shadowrun Novels (Never Deal With a Dragon, Choose Your Enemies Carefully, Find your Own Truth)
#1003 (1992, cover: 2nd ed. GM screen with "1992 update")
* The World of Shadowrun
* Hunter & Prey
* Shadorwun Products for 1992 (Shadowrun, Second Edition, Shadowbeat, Shadowtech, Neo-Anarchist's Guide to Real Life, Darkangel)
* Shadowrun Novels (Changeling, Never Trust an Elf, Into the Shadows)
* KA*GE
#1005 (1993, cover: Striper:Assassin with "1993")
* Voices From The Past
* Shadowrun Products for 1993 (A Killing Glare, Striper: Assassin, Corporate Shadowfiles, Tir Tairngire: The Land of Promise, Germany Sourcebook, Tir Na Nog: The Land of Youth, Corporate Security Guidebook, Ares Security Catalog 2054, Hralequin's Back, Running Short)
* Tir Noble
* Peace Force Border Guard
I have also been told that a flyer with Post Mortem exists:
Unknown, presumably #1004:
* Post Mortem