It also depends on what you mean by G1:
- The original comics/cartoon universe - then you should try out the Classics (US and UK) collections and ReGeneration One. Both are more or less concluded by now.
- IDW started, with Infiltration
, their new take on the entire franchise, and called that G1. Think of it as the Ultimate continuity in Marvel comics, or a good version of the DC New 52. That's where RID and MTMTE are set, too, as ZeroWolf pointed out above.
Similar for movieverse - do you mean the Michael Bay movies? If so, you want to look at this list: http://tfwiki.net/wiki/IDW_Publishing#L ... ilm_series