ℕ

double-struck capital n

Unicode code point: U+2115

ℤ

double-struck capital z

Unicode code point: U+2124

⊊

subset of with not equal to

Unicode code point: U+228A

♠

black spade suit

Unicode code point: U+2660

♡

white heart suit

Unicode code point: U+2661

♢

white diamond suit

Unicode code point: U+2662

♣

black club suit

Unicode code point: U+2663

♤

white spade suit

Unicode code point: U+2664

♥

black heart suit

Unicode code point: U+2665

♦

black diamond suit

Unicode code point: U+2666

♧

white club suit

Unicode code point: U+2667