The issue of an overlay/icon type thing has come up before in some context. If you search, you may be able to find the thread. I think in the end, I ended up suggesting a mouse over text AKA a tooltip in Windows. The advantage would be the ability to list multiple figures where appropriate. It’s not quite as convenient as an icon, but it still allows you to see what you need to see without clicking and going to the product page. ShareCG has something like this, though theirs also has a larger thumbnail image which wouldn’t be needed here. It also avoids vendors needing to name their products V4 this or that. One can argue they shouldn’t mind but I’m pretty sure some would. Also, again, there’s the problem of multiple figure items.

I’d like to see a more clear indication of required products up front. I see what looks like a dress and try to decipher from those tags clothing mesh texture whatever, whether it’s really a dress or a texture for a dress or accessories for a dress …. I’m talking about freestuff here, maybe the marketplace is more clear - and likely I'm missing the clarity as well. A mouseover would have to be implemented by the site and TBH, I think any icons should be as well, or at least a set provided to make it consistent and not have dozens of different V4 icons/indicators. Making it easy for people to tick off the relevant figures when they upload something and have it done would be ideal IMO. I’m sure someone will be along to say ‘just click on the thing and go look,’ but it’s a matter of convenience and efficiency ÷)

"Democracy is a pathetic belief in the collective wisdom of individual ignorance." - H. L. Mencken