what to follow for best build suport or dps suport builds.
Most popular suport now is:
Wiz 2 - linker 3 (spiritual chain + life line) - thauma 3(damage buffs) -RC (with spiritual chain, share rune of protection) FULL SPR.
For dps suport I like: Wiz 1 - you choice (wiz2 = magic missile, surespell to party. Cryo to freeze enemies. Pyro = enchant fire, but you can buy scroll instead) - linker 2(but no life line ;C) - thauma 3(buffs) - enchanter 2 (buffs +lightning hands for dps) FULL INT.
With both builds you can farm as well (link + thauma)
The Best of RC, linker and tauma are the Mdeff debuffs. Every high end tier Have mob/boss with a sick amount of armor and Have the linker debuffs and the destruction rune debuff make a huge difference on boss like velcoffer. Like shrink body on CM st7
Also my second pj for velcoffer is a tauma 2 enchant 2 and its nice but I do it full spr, after testing a lot its more usefull with full spr by the spirit shock atribute thats deal more damage based on the diff between your spr and the target. Also the difference bel spr and full int was like 5k per basic attk.
Your weapons and your total M damage do the real difference.
I don’t believe in “best” support build, i believe is “most popular” or “different niche builds”. Our fellow friends above already talked about the most popular builds nowadays.
The best build is what works for you. What kind of support you wanna do? Are you going to play in party? Are you playing with friends? What are their builds? What can you offer to make them stronge, ya know? There is no point in be a Chrono in a party full of clerics and wizards where nobody uses auto attack or be a linker in party that has a lot of DoTs…
Think about what you want to bring to the table and go from there, wiz has a lot of good support.
Pyromancer: can only support team paired with Linker to share the Enchant Fire buff. This class’ damage is not so good late game.
Cryomancer: Amazing crowd control. It lacks damage tho.
Psychokino: Amazing crowd control. The damage on this class shines when paired with Pyro (PP+Fire Ball combo), Cryo (PP+Ice Wall combo), Enchanter (Enchant Lightning: Psychic attribute) or Onmyoji (Fire Fox Shikigami: Fire Property). I recommend if you take the Kino path you build everything around it.
Linker: aka mob cleanner. This class is the classic support, you share buffs, you enhance all your party stats, you reduce mob magic defense to it’s lowest and with circle 3 + full SPR build “Spirit Shock” can do a massive damage.
Thaumaturge: Buff damage for party.
Chronomancer: Basically you speed up your party. Has some little other tricks like ressurecting bosses, slow debuff and reset your party cooldowns.
Enchanter: Damage and defense buff for party, increase party SP regen.
So… pick the classes you like and the role you wanna play so we can help you optimize it. 
My support mage is focused in Crowd Control and AoE damage, my build is Cryo3>Kino3>Onmyoji2
Mobs just don’t move near me. My party can clean dungeons without a scratch!