Any low-CR undead/constructs with telepathy? Optionally add Vestigial Twin to grant them a second mental standard action per turn.
Each node is created with the instructions "Send a 1 to your post-nodes if you receive 0s from all of your assigned pre-nodes. Send a 0 to your post-nodes if your pre-nodes submit any other signals."
You now have a NAND logic gate,
which can be used in combination to construct any logic system.
EDIT: Gravetouched ghoul
LM Puppeteer?
CR2 Undead with
1/
4HD (an evil cleric can command 4 of them per level)
Fine size(meaning they can be densely packed)
Int 16/Wis 18/Cha 16 and telepathy
Can interface with humans.