I have some square plastic molds from Michaels and have just got into using Pringles cans (I got a friend to save some for me) after Savingdogs posted about using them.
Hubs is going to make me one of those wooden ones that was recently posted about, sorry I can't remember who posted though but I bookmarked the link with the measurements
A family member uses that land o lakes butter that is mixed with olive oil and the little oval tubs filled about one inch or so make the perfect oval bar for gifting. I have a whole stack of them.
But I have tons of silicone cook ware that I am not that fond of and was thinking I may just pick one to play with(I have several square cake pans) and just cut several square soaps or several longer rectangles from it.
But I like the pringle can ideas. I do have a "heart shaped" bread pan(it is a long heart shaped tube that when you cut them it will make hearts) I got it for making little heart shaped toast points for fancy and just hated using it and cleaning it for bread. that might give it another life other than collecting dust and taking up space.
I have 2 silicone bought molds for oval bars and square bars with a nice raised edge. And I have one that I bought that has since been discontinued because the plastic it was made out of is too hard to pop the soap out of, but it makes half-cylindrical bars that I love to use. Great shape- I hold the rounded side and wash with the flat side. I am thinking of trying to figure out how to make a PVC pipe half-mold. I just have to figure out the volume it would take since I only make 2lb batches. And how to cap the ends removably. And how to make it lay on its side without rolling.