There's also Sources and Sinks (SRC/SNK)
Sources are "always on" and Sinks are "always off" - useful if you need to set a pin to a constant state without needing an external input pin.
Comes in 4 flavours each: "1b" is "one bit" ; "1n" is "one nybble" (a 4-bus); "1w" is "one word" (as in byte, an 8-bus); and "all" where it has all three types of connections in one chip.