Here's the full 10km Adventure Sync Egg pool for Might and Mastery: 12km eggs - also known as 'Strange' or red Eggs - were first made available in October 2020 as part of a Team Go Rocket event.

They of course can also appear in anywhere you'd find a Pokémon, not just the wild - so that includes hatching Eggs, Research task ... the arrival of Magikarp and Red Gyarados, the number is ...