I'm leaning more towards a Grapto, but not entirely. What happened to the rosettes on the perimeter pls? It might help to see a photo w/ all of them.

Thank you all for your input. I am learning a lot these past couple of days! From advice here and on Reddit, my best guess is that I have crassula arborescens, echevaria roundleaf? sedum clavatum? (the rosette one seems to be the hardest to ID), haworthia reinwardtii, and some sort of sedum, maybe s. talinoides or s. ficoides (it isn't big enough to get a clear ID but I know it's not blue). I messed with them again today and separated the rosettes into different pots and now the silver dollar jade is all by himself, hoping to become a "specimen" one day. I am very tempted to go on ebay and buy a whole mystery lot of cuttings! Succulents are so interesting!

The one prominently shown is a Peperomia, I think. Is it only the one that you're asking about?

Dominique - it looks like your plant was rooted in one of those peat cells. Something like Jiffy peat pellets. You add water and they grow and are held together by a supposedly biodegradable fabric. (I have found those fabric cells in flower beds years after planting.) I once received a community pot that had all the plants in these peat pellets. It is not good for the plants, so you need to remove the peat from the plant's roots and repot using a well draining mix for your plant.