Apart from STDs, what other infections can be transmitted through sexual contact?

I'm talking skin infections, fungal, viral infections...
What are some of those infections and how can we prevent them?

Technically any infection transmitted by sex is an STD. But you can get flu viruses from seminal fluids, propably even more common illness also. Condoms are the best prevention. Keep body fluids seperate from each other.

Fetus.