Are there default animations?

Inside that classic sword script, there is this weird block:

local anim = Instance.new("StringValue")
anim.Name = "toolanim"
anim.Value = "Slash"
anim.Parent = Tool

Well, apparently it makes no sense, cause it just creates a StringValue, but actually it plays that an animation... it simply disappears when created and the character moves his arm. Is there a library of animations Roblox uses? how many animations are there and how to access them?

(that looks like an old and deprecated system, but it still works)

I do not believe there are other animations using StringValues, but I know there are plenty of player animations using the Animation Object. Try This link and This link. They should teach you how to make custom animations. If the animation plugin doesn't work then it won't work. It doesn't work for many players. For me it works some days and doesn't work other days.

Ahn, there are these lines in the Animate local script, nice.

local animNames = { 
	idle = 	{	
				{ id = "http://www.roblox.com/asset/?id=180435571", weight = 9 },
				{ id = "http://www.roblox.com/asset/?id=180435792", weight = 1 }
			},
	walk = 	{ 	
				{ id = "http://www.roblox.com/asset/?id=180426354", weight = 10 } 
			}, 
	run = 	{
				{ id = "run.xml", weight = 10 } 
			}, 
	jump = 	{
				{ id = "http://www.roblox.com/asset/?id=125750702", weight = 10 } 
			}, 
	fall = 	{
				{ id = "http://www.roblox.com/asset/?id=180436148", weight = 10 } 
			}, 
	climb = {
				{ id = "http://www.roblox.com/asset/?id=180436334", weight = 10 } 
			}, 
	sit = 	{
				{ id = "http://www.roblox.com/asset/?id=178130996", weight = 10 } 
			},	
	toolnone = {
				{ id = "http://www.roblox.com/asset/?id=182393478", weight = 10 } 
			},
	toolslash = {
				{ id = "http://www.roblox.com/asset/?id=129967390", weight = 10 } 
--				{ id = "slash.xml", weight = 10 } 
			},
	toollunge = {
				{ id = "http://www.roblox.com/asset/?id=129967478", weight = 10 } 
			},
	wave = {
				{ id = "http://www.roblox.com/asset/?id=128777973", weight = 10 } 
			},
	point = {
				{ id = "http://www.roblox.com/asset/?id=128853357", weight = 10 } 
			},
	dance = {
				{ id = "http://www.roblox.com/asset/?id=182435998", weight = 10 }, 
				{ id = "http://www.roblox.com/asset/?id=182491037", weight = 10 }, 
				{ id = "http://www.roblox.com/asset/?id=182491065", weight = 10 } 
			},
	dance2 = {
				{ id = "http://www.roblox.com/asset/?id=182436842", weight = 10 }, 
				{ id = "http://www.roblox.com/asset/?id=182491248", weight = 10 }, 
				{ id = "http://www.roblox.com/asset/?id=182491277", weight = 10 } 
			},
	dance3 = {
				{ id = "http://www.roblox.com/asset/?id=182436935", weight = 10 }, 
				{ id = "http://www.roblox.com/asset/?id=182491368", weight = 10 }, 
				{ id = "http://www.roblox.com/asset/?id=182491423", weight = 10 } 
			},
	laugh = {
				{ id = "http://www.roblox.com/asset/?id=129423131", weight = 10 } 
			},
	cheer = {
				{ id = "http://www.roblox.com/asset/?id=129423030", weight = 10 } 
			},
}