http://runescape.wikia.com/wiki/Quest_experience_rewards
100 - Diamond in the Rough
1,000 - Recruitment Drive
2,000 - Legacy of Seergaze
2,000 - Defender of Varrock
2,812 - The Fremennik Trials
3,000 - Underground Pass
3,000 - Land of the Goblins
4,000 - Icthlarin's Little Helper
5,000 - Cold War
5,000 - Kennith's Concerns
5,000 - Royal Trouble
6,000 - Grim Tales
7,000 - Cabin Fever
7,000 - Darkness of Hallowvale
7,900 - The Grand Tree
8,000 - Troll Romance
9,000 - The Curse of Arrav
10,000 - Myths of the White Lands (you must have at least 55 Agility to claim this optional reward)
10,000 - Recipe for Disaster
13,750 - Regicide
15,000 - Back to my Roots
20,000 - Mourning's Ends Part II
20,000 - The Chosen Commander
20,000 - The Branches of Darkmeyer
25,000 - Rocking Out
30,000 - The Firemaker's Curse
30,000 - The Elder Kiln
35,000 - Within the Light
60,000 - The Prisoner of Glouphrie
110,000 - Ritual of the Mahjarrat
Ofc some of those can't be done with 1 defence, and some don't even exist on OSRS, but it's a start!