An Operational Amplifier or op-amp is a voltage amplifying device designed to be used with external feedback components such as resistors and capacitors between its output and input terminals. It is a high-gain electronic voltage amplifier with a differential input and usually a single-ended output. Op-amps are among the most widely used electronic devices today, being used in a vast array of consumer, industrial, and scientific devices.
OPAMPS are mainly available in these 3 most popular pinouts. You can see them below. You can have a long list of opamps available in microchip,TI,ST and analog devices website. Most of them are available in one of these 3 packages. However in the 741 type pinout ICs, pins 1 and 5 may have other functions like offset null, compensation capacitors, etc. However more smaller packages(QFP) have differnt pinouts. Below pic shows only for DIP and SMD(if available) configurations. And for a practical testing and product making, having the knowledge of common opamps and their 3 types of pinouts (as in the pic below) are enough. However one should always check datasheet before using any opamp.
3 most popular pinout configurations of DIP/SMD opamps
Below is a video link. This video will cover all fundamental informations while choosing an opamp in practical purposes, including analysing parameters, pinouts, and datasheet observation. If you want to get this knowledge you should definitely check it out.