The most classical combo are already listed in Xyx's guide for
spells. Just make a little search for the link!
For the sequencers there's no more to say, I can't find a
better defensive combo than Mirror Image + Stoneskin + Improved
invisibility.
You are protected from ANYTHING. Mirror Image protects you from
area spells, stoneskin from blows and imp inv prevents you from
being targeted (even if you attack, thanx to the shimmering)
The best offensive sequencer is Skull Trap x 3 (Use with caution!)
You'll find in that site good tips even for triggers and
contingencies, but I add a few of mine:
In the classical trigger
Imp. Haste + Tenser + Mislead (killer for fighter mages,
but useful even for normal mages since it cures you and
helps a lot) you can trade mislead for true sight.
Since with Tenser spells are disabled, if your enemies
start going invisible or misleaded this can be very annoying.
If you have true sight active...
Chain contingency: I use it only for defense, at 50% hp.
If you are already immune to normal weapons:
Prot. Magical Weapons + Protection from Energy + Spell Turning
(Immune almost to anything, you can trade P. from Energy for
Mirror Image, but here I prefer the first cause Mirror Image
offers a protection against area spells that's not guaranteed,
while the 75% to all resistances is a sure thing).
Since you are totally immune to weapons, don't put stoneskin
in the "normal" contingency, choose mislead (you can if you
are 18th level)
Or try just experimenting!!!
I tried some defensive/offensive combo, just for when I'm
caught by surprise and get hurt:
Contingency -> Mislead
Chain Cont -> Mirror Image + Simulacrum + Abi Dhalzim
(centered on yourself, it is party-friendly, no harm)
Good when you are suddenly surrounded by enemies! You gain some
time, an ally, and possibly kill most of them immediately!!!
This is very fun: I play without preparations, so sometimes
I found myself in nasty situations, but just when I started
being worried the battle was over!!!!
Well, I fear the possible combinations are too many...
But careful with the chain cont. you planned, you summon
a lot of help but remain vulnerable (AND STUNNED!!!),
and if you reached 50% hp then there's something to worry
about!!
Check Xyx's site!