The Logitech Harmony remotes are programmed online from their IR database. You can check that they have your TV codes before buying. The have at least as many commands as the original remote. It will operate a lot of other gear too.
You can get a remote control that knows your TV, sure. But whether it'll power YOUR TV is unknown.
Take a note of your TV' model number, and go to BestBuy / Walmart / etc. Check the "universal remote" sold here, and check whether they have the codes for your TV.
Most of the major tv brands have it so their remotes will work on all their tvs. You could just find any Vizio remote controller and it would more times than none suit your needs. The only problem you may incur would be any special functions specific to your tv model. But for just turning the tv on and off and adjusting volume, any flatscreen Vizio will work.