For the series of Prince Valiant HCs put out by Fantagraphics, you only have 1-24 in Core.
Vol 28 just came out. You’re missing:
25 - Sept 2022 - $39.99 - 112 pages
26 - Feb 2023 - $39.99 - 112 pages
27 - Dec 2023 - $39.99 - 112 pages
28 - April 2024 - $39.99 - 112 pages