This is completely subjective, so I'd love to hear other people's opinions.
Some weapons are just fun, even if they are not that useful. Some useful weapons are also fun. Here are my personal favorites (I'm not including stuff from pillars or after, because you don't get to use them very long):
10. Bone Javelin. You can get a lot from just one fossil, and they stick in the enemy and do damage, so it feels like you're an ancient caveman hunting a mammoth.
9. Tome of Infinite Wisdom. Whirlwind is satisfying when it breaks grass and thorns (especially in crimson) and the main attack is fun for hitting moss hornets.
8. Scourge of the Corruptor. It almost feels like a summon where you can make corruption enemies, and they flood the screen, seeking everything.
7. Flower Pow. Especially fun against old one's army, where you can hit a lot of weak enemie with the regular attack and kill wyverns with the machine-gun petals you get by holding down the attack button.
6. Rocket launcher. It feels great to get this and then take down the Ogre in Old One's Army tier 2 in seconds.
5. North Pole. This weapon is annoying without feral claws/gloves but with them it covers the whole screen in snow.
4. Eventide. The slightly different angles and colors for each of the rainbow bolts is satisfying, and the piercing feels nice.
3. Tempest staff. It's impractical, but having a bunch of little tornadoes following you that spew out sharks is a memorable experience, and having the ground littered with sharkflesh is pretty funny.
2. Dart pistol/rifle. It's just so wacky. The poison darts are kind of boring but the rest are so unique: crystal darts bounce around and hit enemies around corners or off screen, like in underground jungle; ichor darts spread out and hit big bosses or crowds; and cursed darts carpetbomb.
1. Starlight. It's a rainbow sword that attacks at a million miles per second and requires a lot of risk. Not the best weapon but a lot of fun, especially on weak bosses like Lunatic cultist.
Some weapons are just fun, even if they are not that useful. Some useful weapons are also fun. Here are my personal favorites (I'm not including stuff from pillars or after, because you don't get to use them very long):
10. Bone Javelin. You can get a lot from just one fossil, and they stick in the enemy and do damage, so it feels like you're an ancient caveman hunting a mammoth.
9. Tome of Infinite Wisdom. Whirlwind is satisfying when it breaks grass and thorns (especially in crimson) and the main attack is fun for hitting moss hornets.
8. Scourge of the Corruptor. It almost feels like a summon where you can make corruption enemies, and they flood the screen, seeking everything.
7. Flower Pow. Especially fun against old one's army, where you can hit a lot of weak enemie with the regular attack and kill wyverns with the machine-gun petals you get by holding down the attack button.
6. Rocket launcher. It feels great to get this and then take down the Ogre in Old One's Army tier 2 in seconds.
5. North Pole. This weapon is annoying without feral claws/gloves but with them it covers the whole screen in snow.
4. Eventide. The slightly different angles and colors for each of the rainbow bolts is satisfying, and the piercing feels nice.
3. Tempest staff. It's impractical, but having a bunch of little tornadoes following you that spew out sharks is a memorable experience, and having the ground littered with sharkflesh is pretty funny.
2. Dart pistol/rifle. It's just so wacky. The poison darts are kind of boring but the rest are so unique: crystal darts bounce around and hit enemies around corners or off screen, like in underground jungle; ichor darts spread out and hit big bosses or crowds; and cursed darts carpetbomb.
1. Starlight. It's a rainbow sword that attacks at a million miles per second and requires a lot of risk. Not the best weapon but a lot of fun, especially on weak bosses like Lunatic cultist.