RPG Source Recommendations...

[Solauren]

Looking forward Steampunk, Clockwork/Gears and similiar.

For D&D3E/D20/PF1E.

Any suggestions?

[Pauly]

If you're interested in a fleshed out world, Space 1889 based on an alternate history Earth is fantastic. Lots of supplements and materials that can be used. For my money the best steampunk world ever written.
One thing I would strongly recommend if you use the setting is to make social class an important factor in gameplay.

[Solauren]

Some clarification on what I'm looking for

The Campaign is set in the Forgotten Realms, and will be in the Unapproachable East/Old Empires.

The characters are 12 - 13th level (I forget off hand), and have completed 2 years in campaign already.
(including City of the Spider Queen, but did not go into the center, it was more a 'let's go kill giants')

The group is going to be hired to investigate 2 Rathemar Ruins - the Towers of smoke, and the Ring of Gray Flames.

That's when they'll discover that the Rathermar Empire was Clockwork, Steampunk, and similiar elements in it.

(The Towers of Smoke are going to be mostly destroyed, while the Ring of Gray Flames is going to be a largely intact facillity with a powerful illusion over it).

They'll have to go into Narfel (Gothic Horror theme) to recover control items to open up the Ring of Flames for proper exploration.
(The person that hired them is an ARchmage wthat specializes in constructs, and this would be the ultimate treasure trove for them).

After that, they're going to go into the Old Empires, to try to prevent the creation of an army of Flesh Golems built from the bodies of the dead God-kings of Unther and Mulhourandi.

After that, they'll get sucked into doing stuff amongst the ruins of the Immaskar Empire (including a trip to the Palace of the Purple Emperor and possibly a fight with the Elder Evil imprisoned there) to try to stop the capture of lost Immaskar magic that can block gods off from the Forgotten Realms.

After that, more Rathemar Ruins, looking for anti-demon weapons, as they'll discover the being who's cult they've been up against wasn't a Cleric of Gilgaem trying to revive him like they originally thought -

It's going to be the Demon Lord Eltab. They'll have picked up the sword needed to defeat him among the way, and a method for unbinding him and destroying the Demoncysts.

So, what I'm looking for isn't a usable Campaign Setting persay. It's more 'magic, spells, golems, etc', that could/would be found in that style of setting. I've got the other regions (Narfel - Gothic Horror; Old Empires - Egypt, Bablyon, et all), and Immaskari (Psionics, stuff from the Tome of Magic 3e) covered.

I just was never into Steampunk/Magic-Industrial punk stuff before, but love the idea now.

[Eldan]

You might want to look at Iron Kingdoms for D&D third edition, then. That's an entire steampunk setting that should be very easy to take ideas from.

[Vyke]

Some clarification on what I'm looking for

The Campaign is set in the Forgotten Realms, and will be in the Unapproachable East/Old Empires.

The characters are 12 - 13th level (I forget off hand), and have completed 2 years in campaign already.
(including City of the Spider Queen, but did not go into the center, it was more a 'let's go kill giants')

The group is going to be hired to investigate 2 Rathemar Ruins - the Towers of smoke, and the Ring of Gray Flames.

That's when they'll discover that the Rathermar Empire was Clockwork, Steampunk, and similiar elements in it.

(The Towers of Smoke are going to be mostly destroyed, while the Ring of Gray Flames is going to be a largely intact facillity with a powerful illusion over it).

They'll have to go into Narfel (Gothic Horror theme) to recover control items to open up the Ring of Flames for proper exploration.
(The person that hired them is an ARchmage wthat specializes in constructs, and this would be the ultimate treasure trove for them).

After that, they're going to go into the Old Empires, to try to prevent the creation of an army of Flesh Golems built from the bodies of the dead God-kings of Unther and Mulhourandi.

After that, they'll get sucked into doing stuff amongst the ruins of the Immaskar Empire (including a trip to the Palace of the Purple Emperor and possibly a fight with the Elder Evil imprisoned there) to try to stop the capture of lost Immaskar magic that can block gods off from the Forgotten Realms.

After that, more Rathemar Ruins, looking for anti-demon weapons, as they'll discover the being who's cult they've been up against wasn't a Cleric of Gilgaem trying to revive him like they originally thought -

It's going to be the Demon Lord Eltab. They'll have picked up the sword needed to defeat him among the way, and a method for unbinding him and destroying the Demoncysts.

So, what I'm looking for isn't a usable Campaign Setting persay. It's more 'magic, spells, golems, etc', that could/would be found in that style of setting. I've got the other regions (Narfel - Gothic Horror; Old Empires - Egypt, Bablyon, et all), and Immaskari (Psionics, stuff from the Tome of Magic 3e) covered.

I just was never into Steampunk/Magic-Industrial punk stuff before, but love the idea now.

I recall The Aeronaut's Windlass being quite good.