Unicode symbols are often call Glyphs and they draw a lot of attention in a subject line when used on occasion to draw a little extra attention. There are thousands and thousands of available Glyphs that you can use.

Unicode symbols are often call Glyphs and they draw a lot of attention in a subject line when used on occasion to draw a little extra attention. There are thousands and thousands of available Glyphs that you can use.
In looking at our own data and when weighing in with other industry experts like Digital Marketer we have nailed down 4 core types of subject line copy that consistently drive the top results.