My thoughts on Epic Spells.

[Morphic tide]

So, Epic Spells. They are game breaking, but a bit nonsensical. The Heal seed exactly copies the Harm spell when used as negative energy on a living creature. There are no rules for adding the effects of an existing spell. There are a bizarre number of things you must improvise to make a creative Epic spell, like a spell that makes a permanent super-zombie-golem from nothing with maxed stats and Epic item enhancements, though you can get close with a combination of the Conjure, Animate, Animate Dead, Armor, Ward and Fortify seeds. I'm using www.d20srd.org as my reference because I don't have any relevant books and digging through the internet for a more expansive reference that does not get snarky, include homebrew or does not use a decent level of detail is annoying. There will be a good deal of homebrew, mostly in the form of extra factors and new seeds, though a few spells I think up will be in it. Besides, having DCs over 100 for just decent spells is kinda ridicules, given that you are usually going to have 40ish spellcraft when you first have access to Epic spells as a Wizard. So this is to give a setup for useful Epic spells for those who are first getting them, like an SR: no Dominate Monster or the already mentioned zombie-golem, which is at it's most basic, crunch-wise, a zombie made from an Animated Object corpse

[Morphic tide]

For the start of this, the Factors are a good place. Let's start with the basic stuff made from minor house-ruling and work up from there

DC: Varies
An Epic spell with this effect is considered to always be under the effects of the selected metamagic, with the same limits and consequences of combining different metamagic. The spellcraft DC is increased by 5 times the spell level adjustment of the metamagic(so Intensified is +45 and Quickened is +5, but Sill and Silent are both +5)

DC:+30
An Epic spell with this factor may have any number of additional casters contributing any number of spell slots, may have the casting time increased as desired, may change the XP cost as desired and may increase the backlash as desired, altering the spellcraft DC as appropriate(You get to choose the mitigation on the spot, as needed. But you will need quite a bit of it to cancel that change. The name is a bit misleading, as you can solo-cast it)

DC: Varies
An Epic spell with this factor requires the caster to sacrifice additional spell slots to cast it, reducing the spellcraft DC of the spell as if the spell slots were sacrificed by an additional participant(can be used to build lock a spell by making it require the exact number of spell slots a character of a specific build has, though this makes it so that that build can use only that single Epic spell. If it's a Sorcerer/Taint Wizard build, then you can make a spell with over 1000 unmitigated DC with ease)

DC: +300 to make, no effect on casting
An Epic spell with this factor can be inscribed on a tablet made of a material with a hardness higher than 10 to be leaned an unlimited number of times.(to make a tablet that will let you get started on that awesome Epic Wizard school you've dreamed of)
Special: Requires that the spell be inscribed on a tablet, and the DC change from this factor comes after everything else

DC: +5
An Epic spell with this factor may have a set of spells with identical effects to some part of the factors of the Epic spell be contributed to negate the DC increase of those factors. The spell slots are used when the Epic spell finishes being cast (This does mean that contributing Fireball will 'buy off' 10d6 worth of fire damage, and it gets even worse with higher end effects. However, you must have the spell ready to cast when you cast the Epic spell using it, and it must be that specific spell)

[Morphic tide]

Universal
Spellcraft DC: Varies
Components:V, S
Casting Time: 1 minute
Range: Varies
Area: Varies
Targets: Varies
Effect: Copies spells
Duration: Varies
Saving Throw: Varies
Spell Resistance: Varies
This seed copies one or more existing non Epic non Universal spells without the normal costs or components. The Spellcraft DC is twice the spell level of each spell copied plus 1/2 the experience cost plus 1/20 the GP cost of material and focus components times the number of spells copied. The equation for this is (2*SL+Xp/2+gp/20), where SL is the combined spell level, Xp is the total experience cost of the spells and gp is the combined gp value of material and focus components. The effects of the spells are combined so that all targets get the effects. The range is the longest of the copied spells, the number of targets can be up to the highest number among the copied spells, the saving throws are the highest of each type from the copied spells, the duration is the highest non-permanent of all the copied spells, the area is the highest of all the copied spells and if one spell copied does not allow spell resistance than all of the effects do not allow spell resistance. If the final spell has more than one target, divide all numeric values except backlash damage and casting time by the number of targets. Effects from spells that have an Instant or Permanent duration occur each turn(go ahead, make a Killing Disintegrating Destroying Petrifying Stink Cloud with a duration of forever(permanency makes the thing so much worse). The point is that this is a Epic version of Anyspell, so you make uberspells to kill anything. Besides, 2 1st level spells has a Spellcraft DC of 8, while 3 has a DC of 18, so it will bloat your Spellcraft like mad to mix a lot of spells. Granted 100 days 11 minutes waiting, 46d6 damage and every spell slot you have is little to pay to make a true dead zone that eats Tarrasks by the thousand in 1 turn. Or an area where no one can ever die of anything except including old age, thanks to Last Breath, for the Good people out there, which would also immediately revive you if you died of backlash)



Abjuration
Spellcraft DC: 20
Components: V, S, DF
Casting Time: 1 minute
Range: Personal
Area: 1000 ft sphere
Targets: Area around self
Effect: Adds qualities to area
Duration: 1 year
Saving Throw: Will save negates effects for self for one day
Spell Resistance: Yes, for effects
This seed establishes a sanctuary area that may have a variety of effects. Adding a Mark of Justice effect, using Greater Curse instead of Bestow Curse to determine the effects available, to all in the area as they are in it increases the spellcraft DC by 10 for each rule and 5 for each curse inflicted on those who break the rules. Adding continual healing increases the spellcraft DC by 2 for each 1d6 per round. Adding other seeds doubles the final spellcraft DC. Adding the effects of a spell from the Necromancy School or Healing subschool adds twice the spell level squared to the spellcraft DC and applies the effect to all valid targets each round(2SL*2SL, so a 2nd level would be 16 added to the DC, but a 1st would be 4 added and a 9th would be 324. The doubled DC is only once, but it's more to stop arbitrarily hard to get into areas by mixing it with the Manyspell seed, which has it's own way to deal with the arbitrary power possibility)


School varies
Spellcraft DC: 200(Unlimited Contingent Resurrection is meant to be done)
Components: V, S
Casting Time: 1 minute
Range: Personal
Targets: Self
Effect: Adds a resetting contingency
Duration: Permanant
Saving Throw: Varies
Spell Resistance: Varies
This seed creates an automatically resetting contingency spell that will activate on one or more specific triggers. Add twice the spell level of the spells to be used to the spellcraft DC. Each spell beyond the first adds an extra 25 to the spellcraft DC, in addition to it's normal amount. Each activation trigger may use any number of the spells, but each beyond the first adds 25 to the spellcraft DC. Adding another Epic spell seed adds 50 to the spellcraft DC in addition to it's normal spellcraft DC, and any combination of seeds and factors can be used on one trigger. Universal spells and seeds are not permitted(no Multispell)

[Morphic tide]

Using www.d20srd.org and this homebrew, I will make example Epic spells

Seeds: Manyspell, Slay
Manyspell:Destruction, Disintegrate, Power Word Kill(+66 DC)
Slay: 160 HD(+33 DC)
Factors: Bolt(150ft range, 10ft radius)(+12 DC), Has Metamagic Effect(Intensify, Widen, Still, Silent, Quicken)(+ 75 DC),
Mitigation: Backlash 42d6(- 42 DC)
Final Spellcraft DC: 144
Components: None
Effect: Anything in a 300ft long 20ft wide cylinder starting at you, but not including you, with 100 HP or less dies without a saving throw, anything above that with 180 HD or less makes two Fortitude saves or dies, if they make the save they take 676 damage. However, you take 504 damage if Intensify affects backlash damage, which is harsh for most casters, but temp health may save you. If temp health affects backlash damage, anyway

Seeds:Manyspell, Sanctuary
Manyspell:Inflict Critical Wounds, Create Greater Undead(Devourer), Energy Drain(DC +63)
Sancuary: Rules: May not harm undead(DC +10) Curses: Fortitude, Reflex and Will save bonuses reduced to 0, Constitution, Strength, Charisma, Intelligence, Dexterity and Wisdom reduced to 1(DC +45)
Factors: +400% area(DC +16), Has Metamagic Effect(Intensified, Widened)(DC+50) Permanent(DC *5)
Mitigation: 100 days 11 minutes casting time(DC -220), burn 20,000 XP(DC -200), 42d6 backlash damage(DC -42)
Final Spellcraft DC: 916
Components: V, S, DF
Effect: A 10000 ft sphere makes all who die in it into Devourers, Curses all who harm or resist undead to have 1 in every stat and no save bonuses and every valid target in the area is subject to an Intensified Energy Drain and Intensified Inflict Critical Wounds every round. Great for a Necropolis, remove the Create Greater Undead for a more practical place to live. All those stat and save cripples are to DOOM the fools who dare break the rule

Seeds: Animate Dead, Manyspell
Manyspell:Animate Object, Energy Drain, Mass Inflict Critical Wounds(DC +138)
Animate Dead: Ghoul, 42 HD made and controlled(DC + 45)
Factors: Has Metamagic Effect(Intensified, Enlarged)(DC + 50), Permanancy(DC *5)
Mitigation: 11 minute casting time(DC -20), 42d6 backlash(DC -42), burn 20,000 XP(DC -200)
Final spellcraft DC: 903
Components: V, S
Effect: Creates 21 Animated Object/Ghouls that are getting 40 temp HP per round and 104 healing per round. As I'm combining the stats in a semi-logical way, they have 4d12+20 HP, 25 Str, 25 Dex, 0 Con, 13 Int, 15 Wis, 16 Cha, 70 ft move speed, 5ft reach, Balance +6, Climb +5, Hide +6, Jump +5, Move Silently +6, Spot +7, +2 bite (1d6+1 and Ghoul Fever and paralysis) melee for standard attacks and the same +2 bite and 2 +2 claw attacks (3d3) and Paralysis) for full attacks, counts as both a Construct and an Undead, +2 Turn resistance, CR 4, Multiattack and both Undead and Construct traits. Obviously, the pluses aren't magic. The Claw attacks are mixed with the Slam attack to get 3d3, which has the same minimum and maximum as 1d6+1d3+1, the d10 Hit Dice are made D12, the end result is a bit more powerful than getting one Animated Object of the corpse and one Ghoul, so I added 1 to the combined DC. I'm not including that insane healing in the CR because it can be dispelled, so most who face these things and their maker are able to strip it


Seeds: Resetting Contingency
Resetting Contingency: On Death: Last Breath, When targeted by a spell: Mage's Disjunction, When damaged: Heal, Cure Critical Wounds(DC +391)
Factors: Has Metamagic effect(Intensify)(DC +45)
Mitigation: 100 day 11 minute cast time(DC -220), burn 7,400 XP(DC -74), 42d6 backlash(DC -42)
Final spellcraft DC: 100
Range: Personal
Components: V, S
Effect: You are almost literally unkillable by anything, and even then, you auto resurrect to see more punishment. To be more specific, you have immunity to all spells that can be Disjoined, heal for 404 health each time you take damage that can be healed and have practical immunity to everything that Heal cures. Of course, you will have a LOT of things after your head for this, including several gods and armies upon armies of Maruts. Later, their will be companion spells, one for item protections, one for the even more immortal guardian, one for the armor that will be on you and the guardian, two for the ultimate weapon buffs, two for the ultimate weapons and one to make all that happen at the same time



Seeds: Energy
Energy: 20d6 Electricity damage (+39 DC)
Factors: Has Metamagic Effect (Intensified, Chain) (DC +70), area to target (DC +4)
Mitigating Factors: Backlash 42d6 (DC -42) burn 4,200 XP (DC -38)
Final Psicraft DC: 21
Range: 300 ft
Components: V, S
Effect: Target one enemy to deal 240 damage to, then up to 40 extra targets within 30 ft of them are hit for 120 damage. Slightly less powerful than the area version, but the catch is that you are able to use certain factors to cut that down a surprising amount. As in 0 cast DC with one extra mitigating factor

[Bohandas]

Haven't read it over thoroughly but it looks cool