Oh yeah, already encountered Double Ball (unfortunately). There was a dryad-spamming guy who was equally stupid. These decks are in the meta atm?
Yes and no.
Double Ball is a bit dangerous to play now (it was so obnoxious, that most people included anti-scenario cards in their decks), and some of them, like I've mentioned, switched to swarm decks (those that put out many low-value units on the board to avoid losing something valuable to unconditinonal removal).
Still, The Ball sees a lot of play as a part of a less vulnerable strategy called "Soldier Ball" (where you try to push r1 with soldiers rather than The Ball and basically spam one/two hit kills in round 3). It's every little bit as obnoxious as Double Ball and is harder to counter (listed as tier1 by certain pro teams). This one, thus, can be called meta.
In case of Dryads, it was probably a Harmony deck of some sort. If so, the answer is definitely "yes" again, since Harmony generates A LOT of value, while removing a lot of value from your side. The concept behind it is not that different from The Ball, except it's considerably less removal and a lot more value. Unsurprisingly, it's one of the playstyles that often comes up in "people we don't give gg to" thread.
See a pattern yet?
You can be very efficient while using decks from the Internet, but playing them has certain downsides.
First is that there's no satisfaction of figuring some strong unorthodox combo on your own. Which is, like, 50% of the fun in this game. But let's suppose you don't like tinkering around the deckbuilder, that's fine.
Secondly, if you play Poisonous Harmony, Uprising (especially the Draug variation), or, most of all, The Ball, people will hate your guts and won't gg most of the time. Not that it would lose you a lot of scraps/gold ore, but wouldn't it feel frustrating?
And lastly, and, perhaps, most importantly - they get boring really soon. Since such decks are built around strength and reliability, most games with them are exactly the same, like a Groundhog's Day. Same card order, same easy wins, same unpleasant hopeless defeats against people running anti-meta strategies. I suggest you don't listen to strong opinions about the game (mine included) and peruse every NG card you don't have on your own in the deckbuilder instead. Then decide what is strong and what probably isn't (and consequently test them in real games). Many times you will be wrong in your judgement, but these mistakes will give a lot of insight into the game mechanics.
And yeah, like the guy above said, the balance patch is nigh, and much of the advice we give you may be irrelevant tomorrow.