A few tools will help you in making successful 3D prints. They are mostly used to clean and prep the print bed and to remove support material and finish a completed model.
Do I Need an Enclosure?
A few printers come with an enclosure, but most do not. It's fairly easy to make your own, so there's little reason to look for enclosed printers. If you are printing in PLA and PLA+, an enclosure is not really needed. In fact, people with enclosed printers often open the doors to print PLA for better results!
Some filaments—especially nylon and ABS—are very temperature sensitive and benefit from an enclosure. An enclosure—with a ventilation system—may also be a good idea if you are printing nylon or ABS, to send any fumes outside. You can print some of the parts for the ventilation system and combine them with an inexpensive fan unit and flexible ducting.
If you need an enclosure, you can make your own. Thingiverse has files for the corners, hinges, etc. needed for an enclosure, and you can use clear plastic sheets from Home Depot—or thin wood, aluminum, or even cardboard—for the sides and top. Some plans make use of the inexpensive "Lack" end tables from IKEA, which almost seem like they were designed for printer enclosures! The printer sits on one table, and the other table is used as the frame for the enclosure.
Nylon - and Carbon Fiber Nylon and Glass Fiber Nylon
Nylon is a challenging filament to use and a poor choice for beginners. It requires high temperatures which may require parts upgrades and can wear out inexpensive printers prematurely. Nylon is generally more expensive than more common filaments. It is temperature sensitive and has a tendency to warp and shrink. Because of this, an enclosure is generally needed for successful printing with nylon. It is also needed because nylons may emit noxious fumes when printing. Nylon—like many filaments—must be kept very dry for successful printing.
Carbon fiber nylon or glass fiber nylon are generally even more difficult to print with, and require a hardened steel nozzle, as the fibers can quickly wear out a brass or soft steel nozzle. On the other hand, nylon offers strength and durability and is a very versatile filament. It also has a natural lubricity that makes it an excellent choice for 3D printed tools, radio controlled cars, gears, etc.
ABS
ABS—or Acrylonitrile Butadiene Styrene—is a widely-used plastic in industry. It is famously the plastic used in Lego bricks. It requires high temperatures and a heated print bed. An enclosed printer with special ventilation is strongly recommended because of its sensitivity to temperature (ABS shrinks on contact with air) and because it emits dangerous fumes when printing. ABS is also made out of petroleum, and some recycling centers will not accept it. On the other hand, it has good rigidity and impact resistance. ABS used to be one of only a few filaments available, but now there are better choices for sturdy prints. Recommended only for advanced printers who need the specific qualities of ABS.
A host of polymer filaments are available to the hobbyist or small business. Each has its pros and cons, and some require special printers and/or additional equipment for successful printing.
For Success: Keep your filament dry!
Filaments for 3D printing need to be kept as dry as possible before printing. Some problems with poor-quality prints can be traced to moisture in the filament. Many hobbyists use special dryers that hold one or more spools of filament. If in doubt, dry it out! A temperature of 50-60° C. is used to dry filaments. To keep them dry, store the spools in airtight containers with moisture-absorbing materials like silica gel to keep the filament dry. PLA is perhaps the least likely to require special treatment, but all filaments should be kept as dry as possible.
PLA (and PLA+)
Polylactic acid is the most common 3D printing material, as it combines low cost, good strength and easy printing. PLA is also made of environmentally friendly, recycled material, is biodegradable and comes in a wide variety of colors. Many people start with PLA/PLA+ and stay with it. It's an excellent filament. Its primary weakness is that it can warp or deform in high temperatures (like a car on a hot day). It should also out of direct sunlight because of temperatures, and because some of the pigments used to color PLA are not very UV resistant and may fade or discolor.
Wood PLA
"Wood" filament is a mixture of polymer and wood fibers, and the finished printed material looks like wood. Wood filament can be sanded and/or stained, just like natural wood. As far as printing, it behaves like PLA.
Advanced Filament
PETG
Polyethylene terephthalate (PET) is a widely used plastic found in water bottles, synthetic textiles, and many other applications. It combines strength, transparency or translucency and light weight. For 3D printers, this plastic is generally available as PETG (glycol modified PET) filament. It prints very well with excellent layer adhesion, a low level of shrinkage, good heat resistance, and good impact resistance. It costs a little more than PLA and prints at higher temperatures than PLA, and may require an all-metal hot end. Getting your printer settings just right for PETG can be tricky, but it can be worthwhile. PETG must be kept as dry as possible. Some users make use of repurposed food dehydrators or special filament dryers.
Be careful in your choice of print bed material and how you prepare it for printing. PETG can stick to some materials and can damage them when you try to remove your object. PETG is also very difficult—if not impossible—to paint. It also resists most adhesives. Overall, PETG is a useful filament for experienced printers who need durable objects, but PETG does not require the very high temperatures of nylon, nor is it as difficult to print successfully.