Serotonin Molecules, although a few things haave been removed for minimalism

_2d files are just that, two dimensional. You can make them taller and shorter to fit your needs

_flat-bottom files are flat on one side and 3d on the other, probably the best for printing

_1hole files puncture one of the atoms so that it can be used as a keychain, pendant, etc

_2hole files puncture the top two atoms so that a chain can be placed through them for a necklace, bracelet, etc

_extrahole files add an extra carbon ring in the crook of the original two, for a pendant, earrings, etc. This does further reduce the accuracy of he model though.

If you scale it down, you should keep the z scale at least 75%, it will be stronger then. This only applies to _2d files however.