The four general different types of pretrial motions are motions that challenge the sufficiency of the case as presented, motions that challenge the legality of the proceedings under the law, motions that challenge or seek to introduce evidence, and discovery motions. Specific motions that are available to attorneys in a case depend upon whether the case is civil or criminal and the laws in effect in the jurisdiction where the case will be heard. There are multiple kinds of allowable motions from courts around the world, but most common law jurisdictions will at least allow motions that follow these four general types.
A pretrial motion is an oral or written request by an attorney in a civil or criminal case asking the judge to rule on a matter prior to the case going to a jury trial. Pretrial motions circumscribe the boundaries of a case, limiting matters or defining what is allowable. A case can often be won or lost on the pretrial motions because they decide the parameters of the story that the jury gets to hear.
Pretrial motions that challenge the sufficiency of the case as presented ask the judge to rule on the case based strictly on the pleadings, or what the plaintiff or prosecution has indicated are the facts of the case. In a civil matter, a motion for summary judgment asks the court to find that there are no material facts at issue and no cause of action, assuming everything the plaintiff claimed in his complaint was true. A motion to dismiss in a criminal case asks the judge to find that the admissible facts presented by the prosecution do not amount to a chargeable offense.
Motions that challenge the legality of the proceedings under the law are particularly relevant in criminal cases. In the U.S., for example, a criminal suspect has certain constitutional rights upon arrest. The police must follow a particular procedure in stopping suspects, detaining them, and searching their belongings. If any irregularities occur, a defense attorney will make pretrial motions challenging probable cause, or the way a confession was obtained.
Evidentiary motions seek to limit or admit evidence. In a civil context, the defense might try to strike a witness because he is not legally competent, or will seek an advance ruling on the admissibility of evidence through a motion in limine. The defense in a criminal case might try to limit certain testimony or the fact that the defendant has committed prior bad acts through a motion to suppress evidence.
Discovery motions can also be made pretrial. These sorts of pretrial motions can be relevant in the criminal or civil context. Discovery motions typically seek to establish the discoverability of evidence or compel the other party to produce documents or evidence that should have been produced as a matter of course.