Correct! The list of relays (both exit and non-exit) is public. There are several tools with web frontends available as well. There are also relays that are not

Correct! The list of relays (both exit and non-exit) is public. There are several tools with web frontends available as well. There are also relays that are not publically advertised but available by special requests if someone needs a "secret" entry point to the network, they are the so-called bridges,