Hello and welcome to the forum OZDevastator!

For a G1 fix - Get the Encore line - cheap and available now in online stores. It's more of to appease the nostalgia in you.

For updated versions of G1 characters- as already mentioned get the
Classics/Henkei,
United
select RtS (reveal the shield),
and Generations 2.0 ( includes certain WOC/FOC figures)

and for the current line - as that will be easiest to get
TF:Prime

If you also want a selected line which is both a quirky version of the Tf universe lore - have a gander at TF Animated line - its a done line but the transalation to toys from the cartoon series is remarkable toy engineering wise (well, in my book anyways) There is also the Tf Animated Almanac for reading material wise for the line - it's a more detailed look and discusses as well as expands/explores on the TF Animated universe lore. A very, very good read - especially volume 2 (only 2 volumes)