Well its certainly not clear cut this time round. Goomy is pretty easily the best counter, but its also a very mediocre pokemon overall. Magby is decent but has to run such an absurd EV spread that its just outclassed in every other role it could play outside of tangela counter. Any pokemon that has to run sleep talk / safety goggles is really pushing it, as your either playing a game of chance or wasting your precious precious item against 90% of the metagame. The faster tangela was interesting but again is forced to run a much more narrow item than eviolite/life orb which most tangela would prefer.
I pretty much just gotta go with vullaby. While yes, ancient power has a very very slight chance to 2hko, and yes rocks makes it a fair bit easier to deal with, vullaby is still easily the best counter to tangela that retmains a reasonable threat against any given team. In the strictest sense, it is not a true counter, but on average it should be able to beat tangela one on one, which is why it gets my vote.
I pretty much just gotta go with vullaby. While yes, ancient power has a very very slight chance to 2hko, and yes rocks makes it a fair bit easier to deal with, vullaby is still easily the best counter to tangela that retmains a reasonable threat against any given team. In the strictest sense, it is not a true counter, but on average it should be able to beat tangela one on one, which is why it gets my vote.