Hmm... Well, you're kind of all over the place right now >.< but it looks to me, by the fact that you chose helmet, you could go for melee. With a summon weapon for cover, you could be a hybrid summoner, but I'm not keen on how hybridization works. I've some tips for you:
- The Underworld does not gain any new enemies until a Mechanical boss is defeated. This makes it relatively safe to stay down there and farm for a Hel-Fire, an ok yoyo which can aid you well. For a more slightly powerful alternative, farm enemies in the Snow biome for an Amarok. Both are yoyos with rather low drop chances, so that's totally RNG.
- The Snow biome's Hardmode enemies can also yield an Ice Sickle.
- If you have a Wooden Yoyo, you can always take that, get some simple materials from the Hallow (and maybe its underground variant) and craft a Chik. Probably not as good as the two above yoyos, but solid and easily available.
- Fishing in the Crimson/perhaps Underground Crimson is dangerous, but could yield a Bladetongue.
- Defeating a Goblin Summoner, a powerful enemy (may be hard for new Hardmode characters, beware!) in the Goblin Army has a chance to yield a Shadowflame Knife.
- Defeating a Crimson Mimic is very hard for new Hardmode characters. I don't recommend fighting them - go for the other options listed - but if you do manage to defeat one, one of its possible drops is the Fetid Baghnakhs, a powerful choice. If a Hallow Mimic is defeated instead, it might drop a Flying Knife. Again, I don't recommend deliberately attacking a Biome Mimic - they are very strong.
- Blood Eels are a very strong (stronger than Wyverns!) worm-type enemy spawned by fishing during Blood Moons. If you manage to beat one (again, can be quite hard) you might get a Drippler Crippler, a good flail.
- Defeating a Clown, a dangerous Hardmode Blood Moon enemy, can yield Bananarangs.
Buying things is always an option. Keep on the lookout for
good stuff from Traveling Merchants.
I've basically just explained everything in the Pre-Mech Boss section of the guide above. These should be pretty solid melee choices, though, so try some out, and good luck!