I watched .hack//Quantum on Netflix and loved it. I would like to watch the rest of the .hack shows as well, but they seem to not be on Netflix or Crunchyroll. Is there anywhere else I can stream them from legally?
i'm not sure on watching the series online but you can buy .hack//SIGN, .hack//Legend of the Twilight and .hack//ROOTS on Madman. .hack//G.U. Trilogy can be brought from Hanabee but it pales in comparison to the game in my opinion. all of these are Australian so they are in Region 4 but you should be able to find them on your local distribution site(s) but it wont be a problem if you have a region free player.
.hack//Terminal Disk is a special that came with .hack//G.U Pre-orders which details the events between the last episode of .hack//SIGN (After the Game) and the first episode of .hack//ROOTS (before the .hack//G.U games) but ignores most of what happens in .hack//Legend of the Twilight, recapping the original games, Aura's disappearance, Project G.U, the R.A Program which destroyed most of The World and the start of The World:R2. i did have a playlist of them on youtube but the videos have been deleted
.hack//Liminality came with the original .hack Games but i didn't get the final episode when i got the last game so i had to download it, each episode follows in line with the game it was released, the last episode being set during the final battle (the server Helba set up to help combat Corbenik).
.hack//Gift should be included with the .hack//Sign fatpack i linked to likewise with .hack//G.U. Returner with .hack//ROOTS. gift is a weird OVA but Returner is like the last episode of SIGN where it concludes the games.
the .hack//G.U games have Online Jack in the game aswell along with a number of 4Koma episodes along with i think a couple of episode of .hack//ROOTS (never watched them since i had them on DVD)
i have no information on .hack//The Movie or Thanatos Report however according to your wikipedia link both are with .hack//Versus game, the first one being hybrid with the game while the second one being unlocked from gameplay much like Online Jack.
SIGN, LotT and ROOTS are a bit old (over a decade) and quite sure was before the concept of streaming videos so i'm not sure where you could view them. VIZ Media or Aniplex might have them i'm not sure as i tend opt for owning the DVDs and wtahcing them in my own time.