Transport Rides 
For a list of transport rides, see Transport Rides
These slow-paced people-movers include miniature trains, monorails, and chairlifts. You can (and are sometimes required to) build multiple stations as destination points. Use transport rides to give guests a scenic view of your park attractions while ferrying them from one location to another. These are especially useful on large parks, as guests get tired and cranky after walking for too long.
Gentle Rides 
For a list of gentle rides, see Gentle Rides
These low- and no-thrill rides are suitable for all guests (especially children). The Ferris Wheel and merry-go-round are examples of gentle rides. Most gentle rides do not involve custom design and tend to take up less space than more intense attractions. Guests frequently ride gentle rides after riding a high-thrill ride, such as a roller coaster, or a thrill ride.
Roller Coasters 
For a list of roller coasters, see Roller Coasters
These are the big draws of any successful park. Depending on your scenario and research, you could have access to many types of coaster technlogies designed to twist the lunch from your brave guests' guts. Most guests prefer roller coasters over all other ride types. Rollercoasters tend to be the most expensive rides, aside from transport rides, which may vary because of length.
There is at least one premade design available for every type of roller coaster. Hover your cursor over the design name to see its statistics and what it looks like. Other ride types, including some gentle rides and water rides, also work this way.
However, you must be careful when designing Roller Coasters, as if a train meets a gap in the track, goes around a corner too fast or collides with another train at high speed, it will crash. In RCT1 and RCT2, a fireball effect will show when the cars hit something, and any and all guests riding the train at the time will be killed, severely damaging the park rating. In RCT3, the same thing happens, but the guests are only thrown around comically rather than dying.
Thrill Rides 
For a list of thrill rides, see Thrill Rides
These fill the intermediate range in intensity between mild rides and roller coasters. This catergory can include the kind of swinging and spinning belly-churners found at your average county fair. Most take up small amounts of space, like the gentle rides, which make them useful for crowded areas that do not have nearby roller coasters.
Water Rides 
For a list of water rides, see Water Rides
Especially in a hot climate, there is nothing better than a ride that gets your guests all wet. Water rides include everything from rented rowboats to water slides and high velocity coasters interacting with water.
Shops and Stalls 
For a list of Shops and Stalls, see Shops and Stalls
Your park will need a number of non-ride facilities, including food stalls, souvenir shops, information booths and, of course, restrooms. These keep your guests happy, by maintaining their happiness, hunger, thirst, and bathroom levels. These are especially important in pay-per-entry parks since park entrance fees and shop/stall revenue are the only sources of income.
Junior Rides 
Note: RollerCoaster Tycoon 3 only.
These rides are similar to Gentle Rides, however they appeal to the younger peeps that appear in your park. Various rides that were considered Gentle in the previous two games may be considered Junior Rides in the third installment.
Pool Slides and Rides
Note: RollerCoaster Tycoon 3: Soaked! only.
Pool Slides and Rides can be thought of as an extension of the Water Rides category. Filling a similar niche, most of these rides are used to launch guests into one of the pools in a pool complex. These are usually single-or-double-seater rides, and they must be connected to a pool complex by means of a staircase for peeps to be able to use them.
Note: RollerCoaster Tycoon 3 only.
This category is composed of rides that do not fit into any of the other categories. Composed entirely of custom-track rides, every ride from this category fit into one of the categories in RollerCoaster Tycoon 2; they have just been replaced.