Some characters I copy and paste... a lot:

— em dash ALT+0151

• bullet ALT+7

  empty space ALT+255

√ sqrt ALT+2555

○ hollow bullet ALT+777

° degree symbol ALT+248

π pi ALT+227

§ section ALT+0167

™ trademark ALT+0153

© copyright ALT+0169

✓ ✔ check mark ALT+10004 

✗ ✘ symbols

λ lambda

🡴🡰🡷🡵🡲🡶🡱🡳  arrows

⋆☆✦✧✩★✸ stars

⚠️ warning symbol

Accents/other characters

á = Alt + 0225

é = Alt + 0233

í = Alt + 0237

ó = Alt + 0243

ú = Alt + 0250

ñ = Alt + 0241

ü = Alt + 0252

¡ = Alt + 0161

¿ = Alt + 0191