Today's satellites are between 50-500 kg mostly apart form cubesats and their larger versions(3U-16U), which have brought the demand for microlaunchers. Rocket Lab's Electron, is one great example. I want to know how many of this small/minisatellite launch vehicles have existed in the past with flown hardware. I know many are in development, but I'm looking only for the ones already flown, if there are any.
Note that payload performance is often hard to compare apples-to-apples as different providers will use different reference orbits (200 km, 28 deg, vs 500 km SSO, etc).
Numerous others have been flown in the past in this small class range. Some, off the top of my head, include: The Scout family (US), Black Arrow (UK), Conestoga (only a larger variant flew, unsuccessfully), Vanguard (intended to be the first US satellite launch, but failed), Juno (lofted first US satellite), VLS-1 (Brazil). I'm sure I'm missing another handful. Many of the early launches were smallish rockets.