You may have heard of A3 and A4 paper, and A3+/A4+ are just slightly oversized versions of their predecessors. They are commonly used for design-based work.
What is Legal Paper Size and Legal Paper Dimension - Updated
A3+ Size in CM - A Paper Sizes
Visual Guide to ISO Paper Sizes
Paper Printing Sizes - A0, A1, A2, A3, A4, A5
Paper Sizes - USA & UK Ultimate Guide - Toner Giant
Different Paper Sizes, Sizes Explained
Printer Paper Sizes, A0, A1, A2, A3, A4, A5, A6
Frame Paper Size
A3 paper dimensions. Free infographic of the ISO A3 paper size.
Paper Sizes - USA & UK Ultimate Guide - Toner Giant
B Series Paper size guide: B0, B1, B2, B3, B4, B5, B6 Paper sizes
Paper Sizes Guide - Absolutely Everything You Need To Know
A3 size Black and White Stock Photos & Images - Alamy
Paper Sizes A1 A0 A2 A3