I recently did a general count of things you can reinforce on the playtest Slayer's signature tools: turns out, it's not actually a huge number of things, and many of these benefits are elements that could realistically be found on gear. Although this isn't a super-serious suggestion, this is a basic proof of concept to show how this kind of mechanic could be implemented as a general mechanic. Here's the basic idea:
* Adornments are special items you can attach to your gear. Each adornment counts as a property rune for the purposes of your weapon or armor's property rune limit, and attaching an adornment to your weapon or armor takes the same amount of time as etching a rune.
* Each adornment carries a special property that you can adjust by Adorning your Items. The Adorn Items activity is a 10-minute exploration activity that is expended once used, and you recharge it when you participate in slaying a creature of your level or higher as you collect a trophy from your kill (this is done automatically). The trophies you collect are displayed on your adornments.
Now with this basic premise, here's a few examples of adornments that would mirror the functionality of several existing signature tool effects:
* Energy Gland: The still-functioning organs of a slain creature coat your weapon in acid, venom, or another substance. Choose a damage type other than bludgeoning, piercing, or slashing; your weapon deals an additional 1d6 damage of the chosen type. You can change your energy gland's damage type each time you Adorn your Items.
* Gore Anointment: Smeared remains from a creature tied to the Outer Planes serve as a makeshift sanctification for your weapon. Choose holy or unholy; your Strikes with the weapon gain the chosen trait. You can change your gore anointment's sanctification each time you Adorn your Items.
* Tempered Pelt: Scale, hide, or carapace from a creature affords your armor additional protection against certain energies. Choose a damage type other than bludgeoning, piercing, or slashing; you gain resistance 5 to the chosen damage type. You can change your tempered pelt's damage type each time you Adorn your Items.
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The premise here is that these benefits would be generally less than what you'd find in existing runes, but would offer the advantage of being much more easily reconfigurable as you adventure. This would basically allow anyone to adorn their gear with trophies in a way similar to the Slayer, using a method of customization that'd be a lot easier to apply and generally more straightforward.
