I asked some friends about leftover roast the other day and here are the responses. I didn’t want to forget my options the next time I have a big lump of beef in my fridge.
hash: onion potatoes in frying pan to brown, put in some (1/2 c maybe) water, cover, cook until tender. lift lid & cook off most water, add cubed beef, salt & pepper. top w/ an egg if you wanna get fancy. 
fried rice, tacos
i have shredded the beef for tacos, vegetable soup, french dip, beef pot pie,
make it into a meat pot pie–use the med white sauce recipe and half it milk with meat stock or meat drippings, add mixed vegies and hash browns or left over potatoes in a pie shell. . Stroganof, Hot roast beef sandwiches.
BBQ, You just put it in a pan & heat it up with some BBQ sauce & it falls apart usually. Oh so yummy!!!
roast beef sandwhiches
homemade fajitas or a pot roast soup
beef enchiladas
french onion soup
