Of all the things I have posted here, this is by far my favorite. Here are some new feats that relate to two old spells, reincarnation and awaken. There is also a feat to allow bring back the ancient dead. Most are suitable for horror games, though one is meant specifically for such.

Reincarnation was a spell shared by magic users and druids in 1/2e (actually it was Reincarnate for druids and Reincarnation for magic users). The difference is druids usually created demihumans or animals and MUs created humanoids. I get why reincarnate was restricted to druids in 3e, but that takes one very interesting spell away from arcane casters. I suggest not only letting arcane casters have it again, but with the following feat:

Thematic Reincarnation

You can bring the dead back to life in a new form.

Prerequisites: arcane spellcaster level 11+.

Benefit: Reincarnate is added to your list as a 6th level spell and spellbook if you use one. In addition, you create the chart of the possible resulting forms. They must follow a theme, which can be a type, subtype, habitat or some thing else the DM allows. There must be at least 12 forms, which may or may not include human. If you want additional forms, you must take the feat again and create a new chart. The DM must okay the chart and should provide some guidelines (CRs, sizes, number of forms and such) before you start designing yours.

The DM also has to decide what can and can not be affected by Reincarnate. Could a wizard cast it on a roast pig to cause chaos at a feast? Or a dead tree or ant? How about a dead demon or elemental? What about eggs and the stillborn? Can new species be created (i.e. can player designed critters be part of the chart or make it up entirely)? And could there be feats that allow some boosting or customization of the resulting form (similar to augment summoning)? Or one that allows the caster to select from a shorter list? In my opinion, there should not be a feat that allows the caster to select the form. The random aspect of the spell is its most interesting part.

Here is an alternate method that comes from something I posted to the old forum:

Alchemical Reincarnation

You can bring the dead back to life in a new form.

Prerequisites: Craft (alchemy) 14 ranks.

Benefit: You can take a corpse and bring it back to life, though usually not in its original form. The soul must be willing. The process takes 2 weeks and costs 10,000 gold pieces. You design the chart of the possible forms and a chart of mutations and drawbacks that are to be applied to the resulting form. There must be at least 12 forms, which may or may not include human. There must be at least 10 mutations and 10 drawbacks. One of each is rolled for the resulting form. If you want additional forms, mutations and drawbacks you must take the feat again and create a new chart. The DM must okay the chart and should provide some guidelines (CRs, sizes, types, alignments, number of forms and such) before you start designing yours.

And something suitably horrific for Halloween:

Forced Reincarnation

You can reincarnate the unwilling.

Prerequisites: the ability to cast reincarnate or have the alchemical reincarnate feat, non-good alignment, arcane spellcaster level 15+.

Benefit: The soul of the creature to be reincarnated can be unwilling to return. In such a case the caster and recipient must make Will saving throws. If the caster's is higher, the result is a normal reincarnation. If the recipient's is higher, he is still reincarnated but the resulting form is selected by the soul. It may have up to 6 mutations or a +3 CR template. In any case the resulting creature is not controlled by the caster.

In Kobold Quarterly 18 there is an article on synergistic magic, the fusion of two spells to come up with an effect that is greater than either. After much thought, the only spell that I can envision being used to enhance Reincarnate is Clone. As a 9th level slot, the result is two creatures. As a 10th level slot, it is four. As an 11th level slot is it eight. And so on. How the cloned reincarnated creatures react to each other depends on their alignment and intelligence.

And a feat to allow bring back the ancient dead.

Lure Soul

You can bring the dead back to life even if they have been dead for much longer than normal.

Prerequisites: the ability to cast a spell that brings back the dead.

Benefit: The time that a creature died and can be brought back increases greatly. Raise Dead and Reincarnate increase to one year per caster level. Resurrection and True Resurrection increases to one century per caster level.

Special: This feat can be taken twice. The second increases the time to one decade per caster level for Raise Dead and Reincarnate and 500 years per caster level for Resurrection and True Resurrection.

And another spell that should have a variant for arcane casters is awaken. Druids can use it on the plant and animal monster types and I would think those should be restricted to druids.

Uplift

You can raise the intelligence of non-sapient creatures.

Prerequisites: arcane spellcaster level 9+.

Benefit: Awaken is added to your list as a 5th level spell and spellbook if you use one. You select two monster types that do not include plants, animals or constructs for the spell to function on. The DM must determine which types can be affected. The target creature must have an intelligence less than 3. Otherwise it is identical to the druid spell. If you want more than two types, you must take this feat again.

So some DMs may allow awakened zombies, manes and oozes and others may not. If you want to make the spell heritable, there is a metamagic feat in Mongoose's Quint Guide to Druids that allows spells to affect multiple generations. I would be very suprised if it wasn't in some of their OGC collections as well as the OGC wiki (the level bump is one per generation).