Here is a quick breakdown as well.
Concave - a cheaper priced LED and just that, a cheaper LED. These don't give off too much light and tend to have a wider spread. I wouldn't recommend them at all. Maybe in the backbox if you wanted really low light.
Retros - There are a few styles of these floating around, but the main thing is they have a clear cap. They are going to disperse the light a lot better than no cap, but definitely not ideal for places where the LED can be seen when playing. These can work in backboxes, GI or basically anywhere you want some brightness without being able to see it.
Frosted - These are probably the most popular because they can be put anywhere really. They disperse light really well. Great for backboxes, GI and can be put ni view of where your eyes see as they are not blinding.
Flattop - Primarily it seems PBL sells these. They are not going to be as bright as many of the frosted bulbs out there, but they have a much lower price tag and do their job. They actually dso come in handy when you don't want something to be very bright. Maybe on a game like BSD possibly in certain areas. Doing a full game with these is not overly ideal as it can be a bit dim, but overall it is personal taste.
Super brights - These are a flat top LED with no dome at all on them and a larger LED chip used. I would use these for spotlights or under inserts. Retros can work well for inserts as well. I probably would avoid cool white super brights in inserts as it can be blinding and lead to feeling more of a strobe affect. Also, I wouldn't use them for clear inserts as the same results would happen.
Flexes - The same as super brights, but they have a inch or so strand that sticks the LED ship out so it can be bent directionally. These are super awesome for inserts for the socket is to the side and doesn't get the light to the insert as well. Very flexible in terms of usage on these. They do tend to cost a bit more, so I would use sparingly and more of a "specialty bulb".
Other than those styles I would probably avoid the rest as there are just too many styles and they get confusing. There are of course flashers, but they are pretty simple. Standard 89 or 906 and they flash. Also, there are some specialty types of LEDs like blinkers or odd sizes for a few couple games, but those can be dealt with on a case by case basis and your options for styles are usually limited.
Hope that helps a bit!