I've been thinking about Pink Diamond, and where she may be hidden. After thinking about the major appearances of gem shards in the show, and came to the conclusion that if we've seen Pink Diamond's gem shards yet, they'd most likely be the shards from Secret Team.
The first thing to note about these shards is that they are contained in a Rose Quartz bubble. If Rose Quartz did shatter Pink Diamond, she would have likely bubbled her as well, so if these are Pink Diamond's remains, the fact they are in a Rose Quartz bubble is unsurprising.
The second thing to note about these shards is that when they form, the size of the appendages they form are comparable to those of diamonds and most fusions. We've seen other shards form on screen (Specifically in Keeping it Together), and these gems sizes were nowhere in comparison to the size of the shards (and those shards were fusions, which are typically larger than normal gems).
The third thing to note about these gems, and probably the biggest downfall of this theory, is the color of these gems. If these shards were Pink Diamond's, they'd likely be one color: pink. These shards appear in several colors, most notably Yellow, Blue, and the aforementioned Pink. While it is possible the shards changed color somehow, I find it unlikely they would do so. I also doubt someone as important as Pink Diamond would have their remains mixed in with some other gem's.
I haven't completely fleshed out this theory yet; I'm still developing it. I'm just posting this here for ideas on what else to look for when rewatching Secret Team, or to see if someone can help find any information that either supports or disproves this theory. I'll come back to edit this if I happen to come across anything that either supports or disproves this theory.
i actually think the shards of pink diamond was the moss that turned into gem flowers in the episode "lars and the cool kids"
the shattered limbs however was probably another secret she never told the crystal gems. she might have stolen these shards from homeworld becuase she knew what would happen to them. and what homeworld would do to those shattered gems is turning them into undead frankenstein mutants. and we already know garnet was terrified of seeing them for the first time. if rose didnt know what would happen to those shattered gems then she would think there would be no reason to take dead remains of gems. its just that rose keeps too many secrets from her closest friends and doing that leads to consequences that she is obviously able to avoid.