Favorite thing to do with leftover pot roast?

I would just reheat and eat leftovers.

But, since you want to do something else with it and include the veggies, I’d chop up the meat and dice the veggies, and make soup with it. Use beef broth and add more soup veggies (corn, peas, petite Lima beans, etc. I use frozen) to the broth first and cook them until soft, then add the pot roast and those veggies, along with seasoning, and you have soup.

Yup, we just eat it as leftovers for the next day. I rarely make leftover meat into something else.

Beef and noodles! Yum!

I will usually make a container with all the stuffs for my lunch the next day and with what is left, I will make roast beef sandwiches. I tend to buy smaller roasts so as not to have so much leftover meat.

My parents grind it up with the veggies and make pot roast hash. Even better with a fried egg on top!

I used leftovers to make taquitos.  I worked in a Mexican restaurant when I was 16 where I learned to make them.  I seemed to always end up working a shift when they needed taquitos so I would pull a chair up to the big table and make hundreds of them.  At home, I didn’t quite make that many, but I still made plenty.  My sister’s would beg me to make them.  We would freeze them and then just heat them as needed.  I always planned to make some with chicken, but never did.

Handpies. Just on top of biscuits. Hash. Stew.

Pot roast beef dip with horseradish sauce on a ciabatta. Yum.

This^^^^^^^

I just chop it up not grind it.

I’d turn it into a ragout and serve it over buttered noodles. Sauté some onions and garlic, add some red wine and a can of tomatoes, add the cut-up beef and carrots, and simmer for a bit.
Or beef dip sandwiches.
Or I recently had a short rib grilled cheese sandwich at a restaurant. It was really good and I would never have thought of that.

We just reheat and eat. DH also loves the roast as a sandwich. I try not to make too many potatoes and carrots, so we don’t have leftovers of those. I’m not a big fan of either of them reheated.