No syllabus

Hey y’all! How do you study for exams with no syllabus 😩 I have entrance exams for multiple universities (Math) and they each only offer a sample or two. I feel so demotivated because I’m used to textbooks and whatnot. I tried my best to gather the topics I saw on each sample (the samples cover every topic the respective university will test you on) but I struggle finding similar questions online so I’m not sure how to practice.