A-Shape ("Arbitrary") A19 LED bulbs or general service bulbs, are likely the light bulb shapes we are all most familiar with. It's standard light bulb shape is so ubiquitous that this is likely the first form factor you think of when someone says "light bulb". A19 light bulbs typically come in outputs ranging from 20 watts up to 100 Watts in their incandescent forms.
A19 LED Bulb Replacements: A19 LED bulbs recently started to appear on scene a few years ago. The primary target for these are in applications where A19 bulbs are used such as household lighting fixtures and decorative ambient lighting.