You can also hybridise Guppies and Endlers, though it's not recommended. It's best to keep the few pure Endler strains pure. As most have already been crossed over with Guppies to give the Endlers and Guppies different or better colors.
Also, you can cross-breed Swordtails and Platies, but most actually are hybrids anyway. They have been crossed back and forth a lot to get different colors and fin variations. So you won't get anything special crossing Swordtails and Platies. Sometimes you'll get a male with a stubby Sword, or something like that. Nothing good.