Here are a few ideas:
Browse the Table of Contents of mathematics journals.
Browse the Shelves! Scan the titles and/or thumb through books on a topic you like (such as probability, algebra, game theory).
Check out the websites tab.
Talk to your professors; sometimes just talking to someone else can spark a great idea!
Some Relevant Call Number Ranges for Math:
QA 75.5 - 76.765 -- Computer science. Computer software
QA 150 - 272.5 -- Algebra
QA 273 - 280 -- Probabilities. Mathematics statistics
QA 440 - 699 -- Geometry. Trigonometry. Topology
Call Number: QA 95 .J875 2017
Call Number: QA 99 .B195 2014
Call Number: QA 99 .P664 2013
Call Number: QA 273.15 .S74 2020
Call Number: QA247.5 .H38 2023
Call Number: QA 445 .A24 2020
Call Number: QA 76.9.M35 B466 2024
Call Number: GV 706.8 L49 2013
Call Number: QA 95 .O27 2016
Call Number: QA 267.7 .F67 2013
Call Number: QA 460.P8 K37 2011
Call Number: QA 612.24 .M39 2016
Call Number: QA 95 .J875 2017
Call Number: QA 99 .B195 2014
Call Number: QA 99 .P664 2013
Call Number: QA 273.15 .S74 2020
Call Number: QA247.5 .H38 2023
Call Number: QA 445 .A24 2020
Call Number: QA 76.9.M35 B466 2024
Call Number: GV 706.8 L49 2013
Call Number: QA 95 .O27 2016
Call Number: QA 267.7 .F67 2013
Call Number: QA 460.P8 K37 2011
Call Number: QA 612.24 .M39 2016
Call Number: QA 95 .J875 2017
Call Number: QA 99 .B195 2014
Call Number: QA 99 .P664 2013
Call Number: QA 273.15 .S74 2020