This hybrid domain was originally posted as part of an article on Pathfinder subdomains (where you can see how I built it, as with Heavy Lifting: Guardian Domain).
Abyss Domain (Hybrid)
Associated Domains: Chaos, Evil
Granted Powers: You are tainted by the powers of the abyss.
Fury of the Abyss (Su): As a swift action, you can give yourself a profane bonus equal to 1/2 your cleric level (minimum +1) on melee attacks, melee damage rolls, and combat maneuver checks. This bonus lasts for 1 round. During this round, you take a –2 penalty to AC. You can use this ability for a number of times per day equal to 3 + your Wisdom modifier.
Demonic Minion (Ex): At 8th level the powers of the Abyss grant you a subservient minion of your own. You gain a demonic familiar, as with the Improved Familiar feat using your cleric level in place of the arcane caster level. This is likely to be a quasit or an animal with the fiendish template (per the Improved Familiar feat), but other minions may be possible.
Domain spells: 1st—doom, 2nd—undetectable alignment, 3rd—rage, 4th—lesser planar binding (demons only), 5th—plane shift, 6th—planar binding (demons only), 7th—greater scrying, 8th—greater planar binding (demons only), 9th—gate (demons or the Abyss only).