I am originally from London, Ontario and still go back every summer to our place on the lake in that area.
There are several card shops but I have grown to prefer 2 that I have found to be excellent with owners that are knowledgeable and friendly.
The 1st one is in the northwest section of town named Beyond the Pond (Beyondthepond.ca). Great place to browse both new and vintage. Very good baseball selections and excellent hockey (no surprise as it’s Canada).
The 2nd one is south of London about a 20 minute drive. It’s called Fan of the Sport (fanofthesport.com). Great guy owns the place and they have good selection & excellent prices.
if you are up to a drive of about an hour or so there are 2 excellent shops west of London.
The first is in Chatham named Rocket Sports Cards (rocketsportscards.com). The owner might be the most knowledgeable sports card guy in Ontario - he has a weekly YouTube show that is very entertaining.
The second is in a small town named Blenheim (just south of Chatham) named Stadium Sports Cards (stadiumsportscards.ca). Again great people at the store with excellent selection and good prices.
If you decide to go to any of these places please mention that the Dodger guy from California sent you - they will get a kick out of that.
Have fun, enjoy and happy hunting.
Rick