This is a surprising one for me, so I'm glad to be able to share it.
When I was a kid, I remember seeing a line of Venom toys called "Planet of the Symbiotes". The internet tells me this line came out in 1996, which sounds about right. Symbiotes were all the rage in the mid-90s. I can't say why - even as a kid, I didn't see the appeal - but they were, so these toys didn't surprise me. A year later, they came out with a sequel series called "Along Came A Spider". Each of these lines were named after Venom miniseries that involve these characters, but don't have much in common with them beyond that.
I didn't recognize most of these characters at the time, but that wasn't anything new. I often learned of characters through toys. But here's the thing, which I didn't learn until today: some of these characters didn't have names until they released the toys!
The story behind this group of Symbiotes is that they were created from Venom by an organization called The Life Foundation. They first appeared in Venom: Lethal Protector #4 (March 1993).
In their appearances before the action figures came out, the Symbiotes didn't have names. They referred to each other by their host name. But no one would buy a Symbiote named Donna, so Toy Biz came up with more appropriate names. It's a little tricky to explain who has a toy-original name and who doesn't, so we'll go through them one by one.
Moving left to right on the group photo above, we'll start with Scream. The yellow Symbiote was first designated Scream in Civil War Battle Damage Report #1 (March 2007).
Next up is Lasher, the green Symbiote. It was first called that in Carnage USA #2 (January 2012), although it's an interesting case in that the lettering makes it seem like "Lasher" may be the name of the dog that hosts this Symbiote, rather than the Symbiote itself. It's unclear.
In the middle, we have Riot. The grey Symbiote is first called "Riot" in Carnage USA #2 (January 2012).
After that, we have the orange Symbiote, Phage. Phage is a VERY interesting case. If you go back and look at the toys, you'll see one named Phage. But it's not a Symbiote! It's actually an alien called a xenophage, which is a predator of Symbiotes. Here's a picture of one:
Regardless, they had another Symbiote they needed a name for, and Phage is what they chose, no doubt because it was used in this toyline. Phage's name first appeared in Carnage USA #2 (January 2012).
You might notice the final (pink) Symbiote, Agony, is not in the toyline either. And no toy is named Agony. So I don't know where her name came from. Regardless, these Symbiotes (minus Scream) are part of a task force called the Mercury Team. Each soldier is assigned one of the Symbiotes and keeps them contained until they're needed, then bond with them just long enough to finish the task at hand.
Pretty neat, right? The immigrants that catch me off-guard are always my favorite.
For completion's sake, you might also notice there's a toy we didn't mention: Hybrid. Hybrid's name is from the comics, but it's not its own Symbiote. It's a combination of Lasher, Riot, and Phage, who first appeared in Venom: Along Came A Spider #1 (November 1995).