What you see in Vegas is what the Windows OS has as a registered font. If you need a special font there are archives of fonts that you can purchase from places like Best Buy or even Walmart. Like...
Galaxy of Home Office Help: Fonts
Which has about 1,000 fonts. Some of which are crap and only contain A-Z or something, but some are decent.
Or you can purchase them one at a time from places like Adobe. Those are better font sets but they cost a lot more.
Just depends on what you need and how bad you want it I guess.
Visit some web sites that have the fonts you want and install on your system. A reboot may be necessary but Vegas should see them. Some past threads have discussed WHAT TYPE of fonts Vegas has trouble with. Don't recall offhand which, however I've used lots of differnt font familes with no trouble. Again, it mostly boils down to fonts you already have installed or install in the future.
While it vaires depending on which version of Windows you have you should be able to see the fonts you presently have from Control Panel. If not there should be a folder called 'fonts' as a sub folder under Windows in your root directory.
As you may have guessed there are many fancy fonts, some made just for special events like wedding.