This depends entirely on your definition of remade. I assume you're not talking about simple ports, but actual improvements such as graphical updates and new content. So far to my knowledge the only game that is receiving a ground-up remake is VII, but as far as remastered games pretty much every core game has had at least one remastering.
FFI / II were remastered for Origins, again for Dawn of Souls and once more for mobile phones.
FFIII / FFIV recieved 3D remakes for Nintendo DS that were later ported to PSP.
FFV was remasted for FF Anthology.
FFIV , FFV and FFVI all got GBA versions as "Final Fantasy [x] Advance".
FF7 recently was remastered for the PS4 and, of course, the big multi-part remake is coming.
FF7, 8 and 9 have had Steam versions which tweaked the graphics but I don't believe any new content was added (except 8 offered the "Magic Booster" option which started players out with a selection of magic to help correct the Draw tedium).
FFX-FFX-2 has remasters for PS3/ PS4.
FFXI had multiple content expansions, don't know if that really counts though.
FFXII... uh Fangu this is your territory? I know there is the Zodiac Job System version at least.
FFXIII Trilogy received Steam versions but as far as I can tell these are just ports. They did come with a lot (though not all) of the console's DLC included though.
FFXIV was actually completely remade from the ground up. The 1.0 version was almost universally panned as atrocious hence when 2.0 came out it was marketed as basically a new game (even calling it A Realm Reborn). The gameplay is significantly different though the lore from 1.0 is still canon.