Entity Filters are used at a few locations in PneumaticCraft. They all work the same. In a text box you can specify which Entities to include. It works as follows:

To specify certain Entities, whether they are of the same type ('Creepers') or have the same name (a player called 'MineMaarten'), just put it in by plain name. When you want to specify a certain entity type (animals, aggresive mobs, players in general), you put a '@' in front. Here are all the '@' types, and usage examples:

[prefix{l}]@player: [prefix{}] matches all players
[prefix{l}]@mob: [prefix{}] matches all aggressive creatures
[prefix{l}]@animal: [prefix{}] matches all passive creatures
[prefix{l}]@animal(age = adult): [prefix{}] matches all passive creatures that are adult
[prefix{l}]@animal(age = baby): [prefix{}] matches all passive creatures that are baby
[prefix{l}]@animal(breedable = yes): [prefix{}] matches all passive creatures that can breed at this very moment (they'll consume wheat/carrots/...)
[prefix{l}]@minecart: [prefix{}] matches minecarts
[prefix{l}]@boat: [prefix{}] matches minecarts
[prefix{l}]@living: [prefix{}] matches all living entities
[prefix{l}]@item: [prefix{}] matches item entities
[prefix{l}]@drone: [prefix{}] matches drone entities
[prefix{l}]Creeper: [prefix{}] matches Creepers
[prefix{l}]MineMaarten: [prefix{}] matches an entity named 'MineMaarten'
[prefix{l}]c*: [prefix{}] matches any entity starting with the letter 'c' (like Creepers, or Cows).
[prefix{l}]*pig*: [prefix{}] matches any entity that includes 'pig' in the name (like a Pig or Zombie Pigman).

All matches are case-insensitive, e.g. both "zombie" and "Zombie" will match zombies.

You can specify a sequence of filters with the ";" (semicolon) separator - this is a "match any" function, e.g. "creeper;zombie" will match both Creepers and Zombies.