Instead of listing all of the 50 weapons that would net you this achievement, I will list some useful tips instead so that you can get them in no time at all;
- There are more than 50 weapons in this game. These weapons can be found in nanonite chests, purchased from various vendors and can be obtained by cutting off enemies weapon hands off.
- Every boss also has a different weapon to get so always prioritize to cut of their weapon hands in your first playthrough !
- You can also get various weapons from completing quest, depending however that what decision you will make regarding for those quest.
- IF you will not get this achievement on your first playthough, dont worry because there will be more different weapons on your new game+ mode. All your previous weapons will be transferred to your new game+ save also.
- Not sure if the new DLC weapons would count towards this achievement, I got this before any of these DLC became available.