New 50 bard:

[RogueSpecter]

Where do I go from here after story?

[Merryl]

Talk to Nick Ironheart in vesper bay. If you're all caught up on quests he should have one for you called "a relic reborn".... And then begins the second half of the game unlocking the hardmode dungeons and beast tribe dailies for leveling up your gear.

[Estellios]

To elaborate, head to the Waking sands to start more story quests as well as the hard mode primals. There's several dungeons that unlock at level 50. Most of the hard mode dungeons unlock in Mor Dhona. As for the rest, Amdapor Keep is unlocked from Nedrick Ironheart as mentioned above, Pharos Sirius is unlocked in Aleport, Wanderer's palace unlocks from another NPC in Vesper Bay, and Lost City of Amdapor unlocks at the Conjurer's Guild.