(Yes, I've included them all)
The oldest Minecraft server available is 1.2. I have added JSON files back to Beta 1.7.3. Updated 3/3/14; added 18.104.22.168.8.x
If you want a list of the links for use in batch downloaders, or for whatever reason, look here http://pastebin.com/L5m2YEHP (Note: Only includes client release, beta, and alpha jars. No snapshot, server, or other jars are included in this list.)
Please notify me if there are any errors, whether it be on the PasteBin list or in the post!
Psst! If this helped, please vote this up!