Some clays are not compatible with certain molding materials. I have used Sculpey and monster clay with tin-cure and platinum-cure silicones. Avoid anything with any sulfur. This is a good book about sculpting toys and figurines https://www.amazon.ca/dp/0823095223?ref=ppx_pop_mob_ap_share
I checked my Amazon order history. The ones I bought (back in 2013) are no longer for sale, unfortunately.
There are, in my experience, 2 types of display cube - one is thin plastic and has a lid of some sort. The other is thick acrylic and splits in two pieces. The second one is what you want. You'll know which ones are like that because they will look seamless (because the 2 sections split right on the edges, so there is no visible lid).
Here's some I found on Amazon that explicitly state it is the kind that slide together:
I'd verify that you like the dimensions first though. They fit pretty much any mini-fig, but because they are square there is a fair bit of space around the figure. I had to stop using them because I wanted them in a display case, but I had too many figures and needed to shave some space.
The golf ball version is too small for figures, but perfect for making individual risers. I bought a whole case of those just for that purpose. They have square edges instead of the rounded ones you find on most risers that can cause figs to slip.
Dot Dot Dash is from 2006 so early days, but has some good stuff in it if you're interested in some of the first figures on the scene: https://www.amazon.com/Dot-Dash-Designer-Figures-Character/dp/3899551613
You'll want a non-hardening, non-drying, sulfur free clay. Here's one that'll work.
https://www.amazon.com/Van-Aken-Protolina-Alternative-Medium/dp/B007R5M1F8
Thank you! They’re really worth collecting! There’re so many different series, I actually made a list of all 20 pucky baby series here! I just bought more, but they won’t be arriving till next week. 😭 I’m obsessed with them, they’re quite affordable compare to other collectibles I have, so I’m really happy.
I bought my acrylic risers off of Amazon! here it is! This is one kind that I use, I also use taller ones for the top shelves. I don’t use taller ones on the bottom shelves, because then it’ll be hard to see the figures if you get what I mean! :))
Do you plan on getting any pucky babies?