Most op-amp circuits run from the symmetrical bipolar supply source, let’s say ±15V. The simplest way to generate symmetrical split supplies is to use a pair of 3 terminal voltage regulators. For instance, let’s take two voltage regulators: 7815 and 7915.
If you need an adjustable variant of dual polarity regulated voltage source, you can use 317 and 337 adjustable regulators, where you can trim voltage with a voltage divider, which consists of two higher accuracy resistors:
You may wonder if there are dual 3 terminal regulators in one casing – yes, they are. They are called Dual Tracking Regulators. Dual tracking regulators are available as complete integrated circuits in both – fixed and adjustable versions.
Typically there are 4195 for fixed ±15V, and 4194 is symmetrically adjustable via a single resistor.