These are some of my favorite melee weapons, that I use most of the time.
The list is sorted alphabetically, it is not indicating which are “best”.
The best weapon for a specific mission depends on the type of mission and the type of enemy so there is no such thing as a “best” weapon, it all depends…
Not only is Reaper Prime a great looking melee weapon, it is also very fun to use with the Reaping Spiral stance. This build is great for high level enemies (Arbitrations, Steel Path etc.) as the Condition Overload + Blood Rush + Weeping Wounds combo result scales very well and the large range make it very efficient at clearing a room with lots of enemies.
Remember to select the Naramon focus school with a maxed out Power Spike as this will make it easier to maintain your combo counter.
Hint: Against stronger enemies use a secondary weapon with high status chance and high fire rate to proc lots of status effects before using your Reaper Prime, as this will increase the damage bonus from Condition Overload.
Replace the Primed Smite Infested with whatever faction you are fighting. You may also want to replace the Carnis Mandible with some elemental mod.
Vastilok is a gunblade, i.e. it is technically a melee weapon but it fires a shot like a shotgun without using any ammo. Vastilok is not as powerful as e.g. Redeemer Prime but with the Shattering Impact mod it is my favorite weapon for stripping armor as it fires more pellets than the other gunlades and also has 1.3m punch through making it very useful against groups of enemies. It has the highest status chance of all the current gun blades and high Slash damage.
The build below is very good for stripping armor on high level enemies but also deal lots of Slash damage resulting in damage over time from Slash status procs.
Hint: Vastilok is also great for Condition Overload builds as it fires 9 pellets with high status chance and each pellet has a chance to proc Condition Overload.