Best antenna for a balcony or small garden?

[QSL Exchange]

The most common question from new hams: "I only have a balcony / a tiny garden / strict neighbours. Can I still get on HF?"

Yes, you can. Let's collect what works for you:

• Your space (balcony, attic, small yard...)
  
• The antenna you use (magnetic loop, end-fed, vertical, hidden wire...)
  
• Bands and how well it works