Talk:Chroma/Prime/@comment-25792641-20180925205912

At this point, all relics can be obtained through syndicate relic packs.

As for specific missions, I only know that:

Lith C3 can be recieved from the current ghoul infestation event on the plains Axi C3 can be obtained from higher level bounties.

Neo K2 can be obtained from medium to high rank bounties.

And finally the Meso T3 can be farmed from, at the very least, most Defense missions. Most notably thanks to other comments, Earth's Lith Defense (Rotation C), Jupiter's Io Defense (Rotation(s) A and/or B), and Saturn's Helene Defense (Rotation A).