Effects that increase the total amount of Undead one can control

[Terraneaux]

I'm trying to find some items or whatnot that increase this, and all I've come up with is Undead Master. You guys know of any others?

[Lord Foul II]

I believe there is a juju oracle mystery
there is preparing "command undead" as a spell
there is the unread controlling armor enchantment,
there is the agent of the grave prestiuge class
there is the bone beads
if you are into 3rd party there is the "death mage" with one of the options being having leadership over undead

[Ravingdork]

Anything that increases your caster level with animate dead, then follow up with Spell Perfection.

Sample Character

[Lord Foul II]

Right (though if you're high enough for spell perfection i'd go for the create undead one insteed) Mage's tattoo or a certain iuon stone for example

[blashimov]

Prepping the area with desecrate.