Dude nice. I only recently started Aristotle myself after spending a long time on Plato and some on Xenophon. I'm about halfway through the organon right now and have had to read two short commentaries just to get a foothold and figure out what the hell is going on; it's very different from Plato, and much harder to jump into, but it's coming along.
Honestly almost all of Plato is great. I even enjoyed Laws, so if anyone's going to tell you to just read all of it, it's me. I haven't even reached the Romans for philosophy, and have barely started Aristotle, so unfortunately I can't really give balanced opinions in that genre.
But in terms of history I can definitely help. It's tough to declare any historian as absolutely necessary, as they cover such different topics and are almost always loaded down with boring details.
Livy is the most fun, and I think is the best storyteller. Also has the best account of early Rome.
Polybius is more academic and so sometimes is boring, but is I think the single best "teacher" of reading history in the ancient world; he wrote like Thucydides, but where Thucydides just did something, Polybius would do it and explain to you what was being done, and how you as the reader, should prepare yourself to best understand it. Not sure how valuable it'll be if you're an experienced history reader, but he taught me a lot just how to read, e.g., parsing "causes" from "pretexts," which never explicitly occurred to me before then.
Sallust is probably the only historian with almost no fluff in his writing. Maybe 200 pages total and some of the most indicting history I've ever read, largely because he explicitly mixed a lot of philosophy into his writing.
Tacitus gets a lot of praise on lit, largely because he's gotten a lot of praise historically. He IS a good historian; he's also constrained by a very depressing time period, and is far less fun to read than the adventures of the Scipios and Caesars of history.
Might want to read Arrian and/or Curtius Rufus for a life of Alexander. Haven't reached Plutarch's version yet, but considering the brevity of his other lives, I would guess Alexander deserves a fuller treatment.
As for Plutarch, I'd say if you read just one historian, read him; he can't go into depth in a lot of stories that really deserve it, but he CAN introduce you to those stories and point you to other writers treating them comprehensively.
>am in distress since none of the works I am currently working through are often mentioned by li
Dude welcome to the club. Read for yourself and assume you'll have nobody to brag to. Comes with the territory as soon as you depart from the likes of Homer, Herodotus, and Sophocles.
Hope that helps, but feel free to ask anything else. If you're on the fence about any of those historians (or others which didn't even earn a mention) I can offer a more thorough rundown of their topic/style/worth, and some of my favorite passages from them to see if you like them.