Possible Clues:

• Words made from the initials of others
• Words formed from the initials of others
• Oxfam, Unicef etc
• OPEC, NATO, etc.
• Corny Sam makes words from first letters of other words
• A friend writing SWALK is one of them
• A friend writing for entities formed initially, one can say
• Aids Ernie, for example
• Words formed from initial letters
• A friend with medical degree making inventions such as laser