Ammo, Fireflies and key items do not drop and as Cliff said it can happen that some other things stay but that's a glitch.

I took a risk and tested it with some of my weapons, the demon greatsword, eyeball dagger, and funky driftlander. They all didn't drop but when I tested it on some of the cheaper weapons they all disappeared.

Ah, okay. That aligns with some stuff I've heard about a price threshold where items stop dropping. Wasn't sure if it was true since I never bothered testing it, but that's pretty good to know.

Here is all the items that do not drop of death:

https://pastebin.com/raw/fzXzHdLu

Here is a spread sheet look for what u need

https://docs.google.com/spreadsheets/d/1qc2UknmIh29dpS4UB-fFR1-hf64Ml0ihg3aeKGAceuc/edit#gid=305386971

Another thing I've found out is, loot that is won, or rewarded to a player dosen't drop. eg: tower and lost loot, sticks rewards, and other reward giver NPCs

@Asmerlaz that isn't true you lose lost loot on death, at least some of them.

You only lose lost loot that isnt equipment like: clock or sal egg ect

Mostly all things that you can't use

For some reason, on the spreadsheet it says Fantastic Tophat drops on death...wonder why they made so many of the new gear not drop on death but not one of the most unique and hard to get items.