TVTropes¹ and Wikipedia both class buffing in the "Healer" role.
If you want a term specifically for a class that buffs teammates, I suggest...
¹ Warning - your productivity will suffer if you click that link. :-)
They're a subgroup of what Treantmonk refers to as God(s), or the Controller(s) of Reality in their Guide to Playing a Wizard. It's a rather tongue in cheek breakdown of the party roles, but it's got a core of truth to it.
In many MMORPGs I also called them Buffer, but it's my jargon for them. They don't really have a name, but if we really want to give them one the Support would be the best, but actually the Healer is a support type too. So if we want to give the most correct naming I would use some Buffer-Support, because it declares the role and the type too:
There is no specific term
"Support" is the closest term, but the meaning of "support" can vary wildly by context. A "support" can refer to "someone who buffs", but in most contexts it doesn't just refer to "someone who buffs", I've even seen it used as a catch-all for "not-DPS".
I have seen "buffer" used sporadically in writing, but I've never heard ...
While Support is the most common name—found widely even outside of RPGs, as video games use it frequently as well—it may be worth noting that the official terminology for D&D 4e—the only edition of D&D to officially codify roles like this—is that such classes are “Leaders.” That terminology may be used by D&D 4e players in other systems, even non-...
The term I have heard the most would be Support, as it is their role to assist the other party members.
While in a lot of system Healers double as Supports, or Supports double as Healers, they're not the same thing. It highly depends on the system, though.
For demonstration of these terms: My next character in an upcoming Pathfinder campaign is a "Rogue ...
There is a simple reason why this tactic won't work for long:
The other players
As already stated, this player assumes that the other characters are going to help him to:
Dig the hole
Bury him in it, and
Dig him up again
I don't know about your players, but my character won't put up with that, except perhaps to protect and/or hide a defenceless VIP (...
Have you ever DM'd Dungeon World, or other Powered by the Apocalypse games?
In Dungeon World, there exists the concept of the "Front". A "Front" is a collection of linked dangers which can be engaged by your PCs. The following are examples of "Fronts":
The ravages of the Orc Horde on the outskirts of the mountain;
A nearby wizard is obsessively ...