Sorry if I'm a bit late to the party, but if you're playing on PC, especially with the Steam versions*, have you checked out Nexus Mods? There's a ton of free mods on there for Fallout 3, NV and 4, as well as Skyrim (and the TES games from Morrowind upwards). Some of the content is very well produced (voice actors the lot), DLC sized, and in some cases better than the official game quests and DLC. Some of the mods also allow you to build upon them in various ways, even after you've followed the main questlines (there's one mod that creates an infinite amount of missions for you, although they tend to be go here and kill people).
* If you're playing the Microsoft Game Pass versions and like them I'd recommend getting them on Steam (they're on sale quite frequently). The reason is because of a piece of software called Fallout 4 Script Extender (F4SE) or SKSE (Skyrim Script Extender). It allows us modders to do some stuff that wasn't included in the original scripting language, and it will not work with the XBox version. Most of the advanced mods require the script extender and will refuse to work without it (usually CTD). The Steam version also runs better on my machines, even with a shedload of mods (one of my installs has around 600 mods installed courtesy of merging, converting them to light masters, and other tricks), but your mileage may vary.