Free Model

Free Models are models that are saved in the ROBLOX website for others to use in their places. Free models can be found in the "Develop" tab in the navigation bar, then by clicking on "Library". or by going in Studio's navigation bar and clicking on "View" then "Toolbox".

Infected Models
Certain free models are known to contain malicious scripts (e.g a brick/model that spreads fire upon touching the part(s) with the script). Users who have been around for a while tend to stay away from these kinds of models. A good way to make sure a model doesn't have a infection script is to check all the parts in the model in ROBLOX Studio while paused. Most are found in the form of a weld and the name often says something obvious to it's intention, such as "u got pwnd". These kinds of scripts date back to 2008.

Combating Infected Models
There are a lot of anti-virus scripts and plugins in the ROBLOX website. The bestselling plugin that combats infected models is Ro-Defender™, which automatically detects and removes viruses and infected scripts from inserted free models.

Endorsed Models
Endorsed Models are models that are made by members of RBXDev. They are high quality models approved by the admins that follow specific criteria, including they must work with FilteringEnabled, must look professional, aren't anchored/are intractable, don't use copyright material, and scripts are commented heavily, as well as don't have dependencies of other models (ex: can't require other modules from the site). The people who make these models get some Robux and get their model displayed before all others and have the orange icon. These models will never be infected (see above on Infected Models) because they are made by reputable people and approved by the admins.

Criticism
Free models have received harsh criticism from veteran players of ROBLOX. Much of the community believes the use of free models indicates a lack of effort on the creator's part because they used another person's work (often without giving credit to said person) instead of creating it by themselves. This is because the game's developer shows that they lack the creativity and skill to create a game with fully original assets, which in turn means that they are a bad developer, hence, breaking any trust the end user may have with their game.

Trivia

 * Games which have multiple free models are insulted, as are the creators of these types of games.
 * Using free models is fine, but do not make it obvious to the public that you're using them! You'll most likely be disrespected and have harsh comments.
 * If you insert a model into your game, it may have white text on a black bar with written things like "ELIMINATE MANKIND", "ur gettin pWnz0r'd n00b", etc. This is due to an infectious script within the model.
 * When you open your toolbox, the first models that you will see are models that people made who got the official model maker badge for their models.