These are the characters that appear in the comic book series The Transformers: More Than Meets the Eye, and its sequel series Lost Light.
For characters who hail from its sister series but still play a role here, see this character sheet instead. A smattering of other characters can also be found at The Transformers: Windblade and The Transformers: Last Stand of the Wreckers' respective character sheets.
If you want to see the list of characters for the original G1 series, it can be found here.
Some spoilers may be unmasked.