>>6694893well going off the catalogs for each year from 84 through 90, it looks like this as far as I can tell(this only counts American mainline releases from RiD onward, and doesn't count Timelines or Masterpiece or Alternators figures as well);
1984: everyone has had a modern figure in some form or another
1985: only the Deluxe Insecticons(minus Chop Shop) are missing
1986: on the Autobots side only Eject is MIA, while on the Decepticon side, Runamuck & Runabout(unless we count Cybertron Runamuck as being a modern Runabout) are the only missing ones
1987: all the Throttlebots(except Chas), Crosshairs, Pointblank, and Punch/Counterpunch are missing on the Autobot side are missing, on the Decepticon side just Slugfest, and Snapdragon are missing
1988: Sureshot, all the Autobot Pretenders(except Cloudburst & Landmine), Hosehead, Quickmix, Landfill, the Triggerbots, the Autobot Pretender Beasts, the Sparkabots, the Slamdance duo, Slapdash, and Joyride are MIA, on the Decepticon side Needlenose, the Seacons, Bugly, Finback, Igaunus, the Decepticon Pretender Beasts, Roadgrabber, Ruckus, Windsweeper, Flamefeather, Sparkstalker, and the Squawkbox duo are MIA
1989: pretty much everyone except Octopunch, Bludgeon, and Thunderwing is MIA from this year(not bothering with Micromasters here)
1990: again not counting Micromasters, and as for the new characters who are part of the Action Masters pretty much all of them are missing except Banzaitron, Axer, Krok, and arguably Gutcruncher
so basically while a good chunk of G1's backlog have seen modern forms, there's still quite a few missing
