There are 2. SGLI (Servicemen's Group Life Insurance) and VGLI (Veteran's Group Life Insurance). That's it. SGLI when you're in, VGLI is an option when you retire.

Before 2001, you couldn't even opt out. The day you sign on the dotted line, you're enrolled for 200k unless you talk to your personnel shop and elect a higher amount. Post-2001, you could opt out or elect a lower amount, but us NCOs had to counsel our junior troops why that was a bad choice.