In answer to OPs question about individual packages, traditionally logic gates were sold in 14 to 20ish pin packages, e.g. NOT gates have 2 pins each so you get 6 in a 14 pin package with 2 pins left for +V and GND, whereas NAND gates have 3 pins so you get only 4 in a 14-pin package. Designers had to be very creative in substituting one gate type for another in order to use up spare gates and not introduce a whole new package just to use one gate. Inevitably there were a few leftover gates whose inputs would be tied to GND and outputs unconnected. However, the cool thing now is with surface mount technology and tiny packages, individual gates ARE now available. For example a NAND in a 5 pin package, the 3 pins of the gate and the +V and GND pins just for that gate. It's awesome. While MOST gates are inside chips like say an Intel Core i7 which has billions of gates in it, connected up like adders, multipliers, sequencers, etc... the individual gates are great for interfacing one large chip to another, e.g. one chip might output a request line that goes low when active, and this might need to be connected to an interrupt line on anothet chip that goes high to request an interrupt. So you plonk down a little 4-pin inverter chip (in, out, +V and GND) and Bob's your uncle! Look inside a smartphone or modern laptop and you'll see that enormous amounts of glue like this is used to tie together the various pre-made systems such as camera, touch controllers and so on. Individual gates rock!
cheers, Nick