Wikipedia lists a few methane/LOX engines that have been used in test flights. For example, NASA's experimental Morpheus lander had fifteen or so test flights -- all low altitude, but some higher and longer lasting than StarHopper's hop today. It's also being developed simultaneously with Blue Origin's BE-4 engine, which hasn't flown yet, but has been through an extensive ground test program, and will be used on both Blue's own New Glenn orbital rocket and on ULA's Vulcan. So depending on how quickly the relevant test programs go, Raptor may or may not wind up being the first to be part of an orbital vehicle. (But as neither Vulcan nor New Glenn is currently slated to use it for the second stage, Raptor will very likely be the first to go all the way to orbit.)

Yeah, Raptor is the first full-flow staged-combustion engine to fly, but not the first methalox.

I should point out that John Carmack's Armadillo Aerospace are the ones who actually built Morpheus.

> I think Raptor might be the first Methane-based rocket engine as well.

If I remember correctly, John Carmack's Armadillo Aerospace tried burning methane in an engine. Though I don't think they were the only team - or even the first one.

How can methane be created on Mars? It is a gas right, and it isn't that cold there?

Methane is CH4. Carbon from Carbon Dioxide (CO2) and Hydrogen from Water (H2O).

Stoichiometrically, CO2 + (2)H2O -> CH4 + (2)O2

The process is performed via the Sabatier Reaction, which someone else linked to.

It's a gas at STP here on Earth. It's a liquid when it's being used as a rocket fuel.