There's 4 big changes you'll notice since MOP:
1) Quest rewards and any single source, BOE rare item can upgrade to rare/epic. This means there are some quest rewards that are nice but luckily on a druid you dont need any of them. It also means there are some farmable items you will want. For instance, feathered headdress from Skowl and Boulder Pads from Lo'Grosh out in hinterlands are really good when you get the epic upgrade. Foamspittle staff from murloc oracles in westfall is BIS for f2p druids. Its a shitty grind, get ready.
2) Battlegrounds now reward gear crates for winning. These can upgrade to rare quality that is one item level lower than epics, making most epic upgrades obsolete. You can get chest/legs/bracers/rings/weapons from these. Great for filling in pieces.
3) Random dungeon finder now rewards satchel loot. You can get bracers, shoulders, gloves, cloaks, necks, and rings.
4) Party synching is a thing and its where youll get trinkets and maybe a helm. Long story short, part with another account, click the button in your log that says "party sync" and you'll get to re-do quests. that DOESNT mean youll get a second shot at epic quest rewards. Instead, these replayed quests have a chance to give you a crate and that crate contains loot which might be nice trinkets. Its typically other gear though. Another grind. Have fun.
I'll link my f2p druid below. It's BIS but the shoulders are a lucky quest reward. 4/4 or 3/5 aurora shoulders from a dungeon satchel will be just as good. If you're horde, you get the shoulders and a good helm from the Stonetalon questline quartermaster. But if you're alliance, this is what you're going for.
https://worldofwarcraft.com/en-us/character/us/jaedenar/syncopy