Here are three different mini albums that are all made with the same Petal Card Die which looks like this:
Here are the three shapes along with their boxes to house them in-
I made the boxes by adhering two of the cut outs together (you can get a better view in the following photos). The first shape is the square which is made by cutting off one of the rounded sides and scoring the other three to make a pocket.
The next one scores three of the sides to make the pocket while leaving the fourth side unfolded to make the rounded side.
The third one makes a heart shape by only scoring and folding in two of the sides to make a pocket.
There is a Sizzix die but according to their website it is 'suspended'. I think the Stampin' Up die was retired last summer. It looks like they aren't available anymore except maybe on eBay, but perhaps you already have it or your local scrapbook store has it in their die collection. Now before you think that I just gave you an idea you want to try but won't be able to find the die, you can do like I did and cut them out by hand. Worked just fine.