Reptilians

"Looks like there's reptilians in the Renaissance. So put on your period-appropriate boots because we are going lizard stomping."

- Sara Lance to the Puppets of Tomorrow

Reptilians are magical fugitives from Mallus' realm. After Mallus was freed and his escape opened the door for other banished mystical beings, they escaped.

History
After Mallus was freed from his realm, the Reptilians made their escape as well.

In an alternate timeline where the Fairy Godmother, who bonded with Mick Rory, turned the Legends into puppets, the Puppets of Tomorrow were alerted to the presence of reptilians in the Renaissance period.