Jack | RS UNRELEASEDさんのイラストまとめ

Does anyone recognise any of these?

(Inversely, the first 3 images here are 'big' hands - whereas the last/4th hand is small)

Crawling/Zombie/Skeleton hands

These seem to have been intended for the Meiyerditch laboratory dungeon. However, only one variant of Zombie and Skeleton hand seemed to make it into the game.

(4th hand is much bigger than the other 3)

Bloodveld (yes, that particular one is very tiny)

Graphically updated 'Suit of Armour' monster from the Taverley and Burthorpe update.

Unfortunately, when Taverley Dungeon was later updated, the two suits of armour were entirely removed from the game. This meant the graphically updated version was never added.

Prior to the release of While Guthix Sleeps (November, 2008), Jagex had been foreshadowing and hinting towards the upcoming storyline and Stone of Jas.

Could the mixing bowl from the 2008 Easter Event (18-31st of March) have been part of that?

Imperium edicta

Another fun fact:
The Shadow Pylons inside of Kharid-et were originally conceived when Jagex was working on the (unreleased) second expansion after Menaphos (Expansion 2/Before The Wilderness).

You can see the (much larger) expansion 2 pylon model in this JMod game too.