I find it difficult to get specific information on quests for this skill. An online guide states: "Completing the easy quests Fight Arena, Holy Grail, Waterfall Quest, Scorpion Catcher and Tree Gnome Village will give you a huge boost to your combat level..." - but that is combat in general. Some quests, especially advanced ones, give lamps or similar items that can be applied to ANY skill, so you might use those, too.
But in general, if it is combat experience you want (including constitution), I suggest you just fight a lot. You may want to do most quests anyway, either for the satisfaction of having them done, or for the benefits they give you - including experience in different skills.
In order to gain Constitution Xp you must inflict damage on an NPC or in PvP and you will get 10% of the damage as constitution Xp.
dragon slayer gives 20k str and defence xp
In Runescape, You receive 65 Magic XP for every High Alchemy spell that is cast.
15
Every skill in Runescape needs the same amount of xp to get to lvl 99. The xp until lvl 99 in ANY skill (including Range) is:Approximate: 13,000,000Exact: 13,034,431So basically 13mil xp. ;)
Vampire slayer gives like 5,000 attk xp... but thats about all...
In order to gain Constitution Xp you must inflict damage on an NPC or in PvP and you will get 10% of the damage as constitution Xp.
There is a quest called "The Digsite" .It gives you at least 15,000 exp. Its an intermediate kind of quest and its a lot of fun http://runescape.wikia.com/wiki/The_Dig_Site
maple
Well, any quest that involved a specific skill give you that experience point.
Such quests may exist, but if it is farming experience you want, better just go ahead and do some farming. That will be much faster than any quest.
dragon slayer gives 20k str and defence xp
usually each trout gives you 50xp
Burning Shades, killing Ghasts around the Mort Myre Swamp.
Falador teleport gives you 48 Magic experience.
Temple of Ikov give a decent amount of ranging experience.
You can try:As a First Resort..., Fremennik Isles, The Fremennik Trials, The Grim Tales, Icthlarin's Little Helper, Monk's Friend, Recipe for Disaster, Back to My Roots, Heroes' Quest, and Summer's End quests.