This site is simply a compilation of RPGs I've encountered over the years that caught my attention which fit into various subject categories. Not all come strongly recommended, but usually have some element of interest. These lists are also not extensively cross-referenced, so a game falling into multiple categories may or may not show up on both.
Free, Cheap & Quickstart - Anything with a low price tag.
Space Opera - Anything primarily related to space travel or interactions of people from different planets or habitats. Aliens and FTL a plus.
RPGs for Kids - Games which are either intended for younger folks, or might be suitable for some, even if not specifically intended for it.