What are some practical/useful models you can remember ?

[murphyaa]

A long time ago I designed a heart shaped ring box for a friend to give out to her clients (she sold makeup and jewelry). I don't have the design any more though (7 or 8 computers ago)

[Anze]

Ur right, boxes are allways good choice, also with diverse design style options.

[SCEtoAUX]

Here is a website with a bunch of different box templates you can modify a bit:
Templatemaker.nl free, custom sized box templates
There is quite a lot of different shapes.

You can input the dimensions in inches, cm, or mm for the different boxes. The output is a pdf which sometimes will be on very large pages so you have to pay attention to the size of the box template you want to generate.