On the Yo-Yo website, they prepared a cute guide for copying and pasting different types of keyboard symbols. To make special signs on a full keyboard (not on mobile) use the ALT button and then press any number. Here both the numbers and symbols appear divided into categories for ease of use.
Link below.
Cool signs
Π Σ ∞ ч λʍʌя ʁɹ иɔɯɥɟ βεɘəɐΓΞ ∀⊥∪⊃ ⊂∩∨ ∠∧∃ ❞❝ ⇨№℅ ⅞⅝⅜⅛ ¾¼⅔⅓½¡¿ ®©™ ☭☬☫ 
☩ ☨ ☧ 
☥ ✕ 
✓ ₪ 回 ღ ϟ ʊ ◔ ◕ Δ ◯ ● ◎ ○ ◇ ◆ ▽ ▼ △ ▲ ▢ 
⊗ ✘
☤ 
♥ 
유 웃 
✗ © ® ™ ❧ ❦ ❥ 
☿ 
∞ ✧ ✦ 
✆ 
✄ ♬ ۩ ۞ 
☻ 
☼ ☽ ☾ 
✯ ✮ ☆ ★ ♛ ♚ ♕ ♔♢♦ ♡ ♧ ♣ ♤ Ω ♠ ⊗ Σ ❖ ⌥ ⌘ ஜ ๏ 文 ⑂
smileys
ﺢ ϡ Ü シ ッ ツ ヅ ت ☻ 
Question and exclamation marks
! ！ ‽
⁈
❢
All kinds of circles
◍ ◙ ◘ ⊙ ⊗ ◑ ◐ ◔ ◕ ◯ ● ◎ ○ ❂
Squares of all kinds
☷ ☳ ☶ ☵ ☴ ☱ ☲ ☰ ▯ ▮ ▭ ▬
▩ ▨ ▧ ▦ ▥ ▤ ▣ ▢ □ ■
A
corners
, ┺ ┹ ┷ ┶ ┵ ┵ ┴ ┲ ┲ ┱ ┱ ┯ ┮ ┭ ┭ ┬ ┬ ┫ ┫ ┪ ┪ ┪ ┪ ┩ ┨ ┦ ┤ ┤ ┤ ┤ ┤ ┤ ┤ ┤ ┣ ┣ ┢ ┡ ┠ ┟ ┞ ┝ ┛ ┚ ┚ ┚ ┚ ┙ ┙ ┘ ┘ ┗ ┖ ┕ └ ┑ – ┎ ┏ ┏ ┏
percentage
‱ ‰ ℅ %
X’s
✇ ✘ ✗ ✕ ☓ ☒ ☐
V
√ ✓ 
Pencils
✑✐
✎ 
hearts and species
5 ღ 유 웃 ☿ ♡ ❧ ❦ ❥ ♥
Weather
ϟ ✺ ❅ ° ℉ ℃ ☉ ⊙ ☈ ☇ 
☽ ☾ ☼
stars
-‘๑’- ❂
╮☆╰ ❋ ❊ ❉ ❈
❆ ❅ ✼ ✻ ✺ ✹ ✸ ✷ ✶ ✵
✲ ✱ ★ ✰ ✯ ✮ ✭ ✬ ✫ ✪ ✩ ✧ ✦ ✥ ✤ ✣ ✢ ⋆
Letters and numbers with a circle
➀➁➂➃➄➅➆➇➈➉
➊➋➌➍➎➏➐➑➒➓
ⒶⒷⒸⒹⒺⒻⒼⒽⒾⒿⓀⓁ
ⓃⓄⓅⓆⓇⓈⓉⓊⓋⓌⓍⓎⓏ
ⓐⓑⓒⓓⓔⓕⓖⓗⓘⓙⓚⓛⓜⓝⓞⓟⓠⓡⓢⓣⓤⓥⓦⓧⓨⓩ