Short answer. Only rebutting evidence, as a rule. Rule 30 provides that once the parties have gone through the order of trial, they may then respectively adduce rebutting evidence only — unless the court, for good reasons and in the furtherance of justice, permits them to present evidence on their original case instead.
What the law says
The parties may then respectively adduce rebutting evidence only, unless the court, for good reasons and in the furtherance of justice, permits them to adduce evidence upon their original case
Rule 30, Section 5 — Order of trial. Read the full provision →
The order in which evidence is presented
Rule 30, Section 5 lays out the sequence of trial step by step: the plaintiff shall adduce evidence in support of his or her complaint, then the defendant shall then adduce evidence in support of his or her defense, counterclaim, cross-claim and third-party complaint, followed in turn by any third-party or fourth-party defendants and parties answering a counterclaim or cross-claim. Each side's main presentation of evidence has its own place in that sequence.
After that sequence: rebutting evidence only
Once the parties have gone through that order, the rule narrows what comes next: the parties may then respectively adduce rebutting evidence only, unless the court, for good reasons and in the furtherance of justice, permits them to adduce evidence upon their original case. As the default rule, new evidence at that stage is limited to what actually rebuts what the other side presented — not fresh evidence supporting your own original case all over again.
The narrow exception for good reasons
The rule does not make this an absolute bar. The court may, for good reasons and in the furtherance of justice, allow a party to present evidence on their original case even after this stage. That is framed as an exception the court grants for a genuine reason, not something a party can simply invoke as a matter of routine to reopen their case, so a party hoping to rely on it should be ready to explain to the court why the evidence could not reasonably have been presented earlier.
What happens once the evidence is finally admitted
Once this stage concludes, Rule 30 moves the case toward resolution: upon admission of the evidence, the case shall be deemed submitted for decision, unless the court directs the parties to argue or to submit their respective memoranda or any further pleadings. Rebuttal evidence, in other words, is generally the last substantive evidence a party gets to offer before the case is ready for decision and the court moves toward resolving it.