Full list of the originals:
* Blackmoor - Used to spawn on liches and lich lords, does not currently spawn.
* Blood Spawn - Original tan colored one is still rare, but blood spawn was reproduced from cocoa pulp. The resulting blood spawn is redder than the original.
* Bone - Currently spawns and is used to craft bone armor
* Brimstone - Rare, common price I've seen is 10m.
* Daemon Bone - Currently spawns on monsters in the non-gauntlet part of Doom. Also used in Mysticism.
* Dead Wood - Used to spawn on corpsers I believe. Maybe reapers. Currently not spawning.
* Dragon's Blood - Currently spawns by skinning a reptilian creature. Used in Mysticism.
* Executioner's Cap - Currently spawns on whipping vines.
* Eye of Newt - Rare, haven't seen one for sale. Gold colored "eye of newt" exists, I believe, made from lucky coins (not 100% sure on that though).
* Fertile Dirt - Purchasable from Mystics in Ter Mur, used in mysticism
* Obsidian - Rare, haven't seen one for sale.
* Pumice - Non-spawning, but was (and may still be?) made from old Tram/Fel moonstones as well, so it is decently common compared to eye of newt, brimstone, etc. Common price I see it is 1m.
* Serpent's Scale - Not spawning, but all serpent's scale became nox crystals with AoS.
* Vial of Blood - I believe all "Vial of Blood"s became daemon blood with AoS.
* Volcanic Ash - Not spawning, but all became grave dust with AoS.
* Wyrm's Heart - Rare, and from what I've seen, the most expensive. Common price I've seen it is 20m.
Also, from my limited experience, the current non-spawning ones would be grouped into different categories of "rare".
Have not spawned since cut necromancy skill, or been recreated in any way (that I know of): Wyrm's Heart, Obsidian, Brimstone
Have not spawned, but have been recreated in some way: Eye of Newt, Blood Spawn, Pumice
Spawned on monsters for a long time after necro skill was scrapped, but does not spawn now: Blackmoor, Dead Wood