Lizards were a type of reptile with tympanic membranes close to the skin. (COMIC: Ripper's Curse)
In the 1970s, Professor Tansbury's experiment resulted in the creation of a giant lizard. (COMIC: The Tansbury Experiment)
In the 2010s, Bill Potts saw a film on Netflix about lizards in people's brains, controlling them. She related this to what she was seeing with Heather, and the Twelfth Doctor ridiculed Bill for coming to this conclusion first, of all things. (TV: The Pilot)
On Uxarieus in 2472, the IMC tried to drive off the the colonists living there by using a robot and projections to make it appear that giant lizards were attacking. (TV: Colony in Space)
The First Doctor, John and Gillian visited a planet inhabited by giant lizards which briefly captured them. (COMIC: Lizardworld)
The Seventh Doctor briefly turned Chris Cwej into a lizard. (PROSE: Sky Pirates!)
While scanning space for Cyber-Warships, the Seventh Doctor spotted a lizard coming out from hiding and realised the ships were camouflaged. (TV: Silver Nemesis)
Chromatic lizards were a species native to Rokhandi. (COMIC: The Friendly Place)