I'm currently saving up for various car parts for an older car. I'd been using an american site like rockauto as it was easy to filter out and find the exact part I need.
Are there any Canadian alternatives I can look for?
I don't think it's possible. Rock Auto doesn't list the country of manufacture. I'm pretty sure it's because very often the exact same item (part, brand, and serial number) is made in different factories in different countries. I've ordered the exact same thing and sometimes it says made in China, other times Mexico for example. I'm pretty sure this is true regardless of which retailer you order from, so unless you are physically looking at the item before you buy it, you probably won't be able to know. And these days, even going to my local parts store, they will most of the time need to order parts in from elsewhere.
If you're asking if there's a Canadian alternative to Rockauto, I'd also love to know.