Here is a list of some commonly used Unicode characters that you can copy and paste:

Arrows:
→ Right arrow: →
← Left arrow: ←
↑ Up arrow: ↑
↓ Down arrow: ↓
↔ Left-right arrow: ↔
↕ Up-down arrow: ↕
↖ Northwest arrow: ↖
↗ Northeast arrow: ↗
↘ Southeast arrow: ↘
↙ Southwest arrow: ↙
⇒ Double right arrow: ⇒
⇐ Double left arrow: ⇐
⇑ Double up arrow: ⇑
⇓ Double down arrow: ⇓
⇔ Double left-right arrow: ⇔
⇕ Double up-down arrow: ⇕
⇖ Double northwest arrow: ⇖
⇗ Double northeast arrow: ⇗
⇘ Double southeast arrow: ⇘
⇙ Double southwest arrow: ⇙

Shapes:
○ Circle: ○
● Filled circle: ●
□ Square: □
■ Filled square: ■
△ Triangle: △
▲ Filled triangle: ▲
▽ Inverted triangle: ▽
▼ Filled inverted triangle: ▼
◆ Diamond: ◆
◇ Filled diamond: ◇

Stars and Asterisks:
★ Star: ★
☆ White star: ☆
✦ Star with rays: ✦
✧ Small star: ✧
✪ Circled star: ✪
✯ Circled white star: ✯
✻ Asterisk: ✻
✼ Six-pointed asterisk: ✼
✽ Heavy asterisk: ✽

Symbols:
∞ Infinity: ∞
☺ Smiling face: ☺
☻ Black smiling face: ☻
☼ Sun: ☼
☽ Waxing crescent moon: ☽
☾ Waning crescent moon: ☾
♀ Female symbol: ♀
♂ Male symbol: ♂
♡ Heart: ♡
♢ Diamond (alternate): ♢
♣ Club suit: ♣
♦ Diamond suit: ♦
♤ Spade suit: ♤
♥ Heart suit: ♥

There are many websites that provide a list of Unicode characters that can be copied and pasted. Here are some examples:

1. Vertex42.com provides a list of math symbols, emojis, dingbats, and other miscellaneous symbols that can be copied and pasted into Excel [1].
2. Wikipedia has a complete list of Unicode characters, including 161 modern and historical writing systems, as well as several symbol sets [2].
3. ThrewTheLookingGlass.com has a classified list of emojis, symbols, Unicode characters, and anything else you can think of [3].
4. Symbl.cc is a Unicode web service for character searching. It allows you to search, copy and paste your favorite characters including emojis, hearts, slogans, arrows, stars and many more [4].
5. W3.org provides a list of Unicode characters from 02600 to 026FF, including box designs, geometric shapes, and various symbols [5].
6. UnicodeEmoticons.com provides a list of 15,000 Unicode symbols for emojis in different categories, including smileys, animals, food, sports, and more. [6].
7. CodeCracker provides a list of some well-known Unicode characters

These sites offer a wide variety of Unicode characters that can be copied and pasted into any text editor or application that supports Unicode.