So, I didn't realize there were a couple more pages of replies and so didn't see people talking about Mechs.
I've killed all 3 mechs with melee:
Destroyer? lol, Bladetongue can kill that in 30-45 seconds.
Prime? Yelets.
Twins? Yelets, again. But gotta be careful, as Spaz's green flame makes it hard to get hits on him without getting hit yourself, but if you're patient and know when to run away and when to dash in for a few hits, you can succeed. I've done it before.
That just leaves Plantera. Before 1.4, I always made a Terra Blade to make Plantera easy-peasy, though I suppose a Yelets would do with some creative dodging and some arena prep. And the Golem is laughably easy.
The cultist is done with the Terra Blade and the Eye Yo-Yo (the Blade makes quick work of any summoned wyverns), and then the Moon Lord is Solar Eruption for the first phase, and Daybreak for the second. Fishron, I usually just skip, as I see no real reason to kill him, but if I had to kill him, I'd probably use either Daybreak or Eruption, depending on phase and range.