Heres some more info which i've found browing scapeboard, and talking to people in Runescape.

Shadow Warriors Drop List
By: Neo Mario
Written By: Neo Kirby

Bones (all the time)
Herbs (Kuarm, Marantil, Harrlander, Guam, Tarromin, Candatine, Dwarf Weed, Irit Leaf)
Coins (8-16)
1 Dragon Spear (rare)
Uncut Gems (All)
1 Left Half of Dragon Square (rare)
1 Chaos Talisman
45 Air Runes
2 Blood Runes
2 Death Runes
3 Cosmic Runes
1 Black Long Swords
1 Black Dagger (p)
Rune Javalins (5) (uncommon)
1 Adaminite Spear
1 Mithril Bar
1 Black Knife
1 Weapon Poison (1 dose)

Notes:
Only found in Legends Guild. The shadow warriors are a good choice monster for drops, although from my personal experience, they are crowded ~ Swifty.

Chaos Talisman info: It seems that a popular choice for Chaos Talisman drops is... The Chaos Druid! Yup, this lower lvled NPC has been reported to be dropping the talisman quite alot.

Cosmic Talisman info: Hmmm.. well it seems that alot of people are getting their Cosmic Talismans from caskets. For those who don't know, Caskets are obtained when fishing with big nets and are a members only object. Mysterious Old man has also been reported to hand these out (random event).

Nature Talisman info: It is now being reported that Ice Giants are dropping these, as well as Moss Giants! Skeletons and HobGoblins are also being reported to drop them.

Ill try and get some more info soon!