Thanks to Maverick I took the opportunity to upload the demos I have gathered over the years. These are:
ca. 12 GB of Quakelive, lots of Quakecons, ASUS Cups, IEM etc.
ca. 13 GB of Quake 3, lots of ESWC, WCG, CPL etc., CPM, OSP, VQ3 included.
ca. 47 GB of QW. All stuff I downloaded over the years, some of now unknown sources and close to everything from challenge-tv.
ca 2 GB of NQ, very random.
ca. 2 GB of Quake 4, sorted by point releases, including a folder with all q4max releases I have.
Well, don't hold your breath, its partly stuff I downloaded from challenge-tv and then the complete challenge-tv archives on top of it so there are likely to be lots of demos and their zip version with another name. However there is also some weird stuff I once mass-downloaded and can't remember where it came from, look into the 'dadied' folder.