The first time connecting to a VyOS router with SSH it asks the user to verify the fingerprint.
The following command displays the available public keys one page at a time.
for PUBKEY in /etc/ssh/*.pub; do ssh-keygen -l -v -E sha256 -f ${PUBKEY}; done | more
This would make a great op-mode command such as 'show ssh fingerprints'
VyOS could also hint the user that these keys are stored in /etc/ssh as per a regular linux system and that commands like cd/ls/ssh-keygen can be used.
See Forum for background
https://forum.vyos.io/t/how-to-verify-ssh-fingerprint-of-a-vyos-router/12277