I like the ASP Baton for the fact of it being a really well balanced out weapon. With good attack damage, good equipped walk speed, and good stab time. Nothing is really too overbearing. This is a perfect beginning knife to find out which category fits you best.
All melees are different. The best one depends on your play style. Jack of all trades? Knife. Light, fast and does moderate damage. If you’re a heavy tanker guy, go for the two hands. The baseball bat is ok, but the hattori really shines if you’re a sniper build, due to its range and quickness. The Chosen One is a bit of a mix, since it isn’t as good as hattori but better than the long sword.
One hands? Karambit for PDWs, everything else for assault rifles.
My favourite melees are Hattori, Cricket Bat and ASP Baton.
My best melee is the nordic war axe which I have 1.5k kills with then the chosen one and morning star. But my favorite melee to use which I love is the zero cutter. The zero cutter is shorter than the range of reaper, it's movement speed is faster than all of the two handed melees. It swings faster than the chosen one and does around the same damage. In my opinion the zero cutter is one of if not the best melee overall.