I would like to know if with Vanitygen it is also possible to generate thousands of addresses with keys and output them in a file (regardless of the pattern of the address) and at the same time generate addresses of different altcoins like Ethereum, Litecoin, Dogecoin etc...?

And importantly is there a version of Vanitygen that runs with a GPU like Nvidia?

Unfortunately there are so many forks that I don't know which one is safe and which one supports exactly these functions.