Support Masteries

http://champion.gg/

Depends on your playstyle and the champ you are using..

Windspeaker's if you love spamming shields/heals. Good for all stages of the game, though buffs may be subtle. It actually works on Bard. Bond of Stone if you want to be tankier in general. It ALSO works on Bard. Thunderlord's if you are crazy for that early lane damage. Good for early game, mediocre if you built scaling items, unnoticeable if you don't.

I'm not too sure about Strength of the Ages, but if you like an extra kick of max HP, then no one's stopping you.

Anything else are kinda bad unless you're some midlane mage mage "supports" like Annie/Brand/Vel'Koz/etc, where your damage matters.