Pick-ups by universe

Quick answer

Pick-ups sit by faction lights. Most belong to one universe, and the Purple Sun of Shyish can damage you.

They sit by faction-themed lights. Auroch's 19 August post says most are unique to one universe, even when two look similar.

Pick-up	Universe	What it does
Frag Grenade	40k	The ordinary grenade. Also the Legend of Catachan's starting weapon.
Melta-bomb	40k	Delayed thermal blast. Kite the mob in, then leave.
Blast Template	40k	A huge clear. Some enemies resist the insta-kill.
Hellfire Ammo	40k	Ranged damage up for a while, plus Poisoned. Tied to Sternguard, and to Malum Caedo, in that post.
Purple Sun of Shyish	Age of Sigmar	Damages anything in the light, you included, then leaves.
Ravenak's Gnashing Jaws	Age of Sigmar	Tethers to you, bites what is near, applies Burning. Not picky.
Suffocating Gravetide	Age of Sigmar	Stuns, then the struck enemies flee for a moment.

The Purple Sun is the one that ends a good run. Step out of the light. How these sit next to Synapse and a red screen is how a run actually goes. The open-ground versus corridor version is two settings, one screen.

Official screenshot