Brand
Olympus came to digital interchangeable-lens cameras with Four Thirds, a DSLR standard it announced with Kodak in 2002, and the E-1 in 2003. In 2008 it and Panasonic released Micro Four Thirds, a mirrorless version with a much shorter mount, and the first Olympus PEN followed in 2009. The OM-D line began with the E-M5 in 2012. On January 1, 2021 Olympus handed its camera business to a new company, OM Digital Solutions, which now sells cameras as OM System. The lenses haven't changed, so an Olympus body still takes OM System and Panasonic Micro Four Thirds lenses.
3 cameras we cover.

Olympus · Mirrorless
200K ratedMicro Four Thirds 20.4 MP · Micro Four Thirds mount · 2016
$525–$825 typical ask
74 on eBay

Olympus · Mirrorless
400K ratedMicro Four Thirds 20.4 MP · Micro Four Thirds mount · 2020
$875–$1,100 typical ask
46 on eBay

Olympus · Mirrorless
Micro Four Thirds 20.4 MP · Micro Four Thirds mount · 2019
$700–$900 typical ask
75 on eBay