Nostalgic - What version are true to the original animated series I watched in the 80s

I'm wanting some transformers to take me back to my youth and the collection I once had. I know so little about all the other permutations of lines of the series. If I'm looking for ones that are most similar to the original cartoon from the 80's what am I looking for?

I don't need originals, replicas are great. It's more just for fun than collecting. I'm just confused on what to look for and where?

Also, I vaguely remember seeing an Optimus Prime from the cartoon that was redone but metal and larger. I've never been able to find it again and I regret not buying it at the time. Any help would be appreciated. Thanks in advance!