Her office at the Scottish Parliament has been flooded with hundreds of emails and phone calls from people, many calling for a permanent tribute.
No formal suggestions have yet been made but Christine Grahame, the SNP MSP and a close personal friend of Ms MacDonald, said a memorial should be "fun".
She said: "It's too early to think about a permanent memorial. There is already a lighthearted suggestion to name the Holyrood bar 'Margo's Snug' because that's where we would all go to look for her.
"Lots of ideas will come forward but whatever is chosen would have to be fun, something that would capture her energy, vivacity and sense of mischief.
"For me, statues don't convey vivacity. We need something that captures that twinkle in her eye."
Independent Lothians MSP Ms MacDonald, who had battled Parkinson's disease, died peacefully at home in Edinburgh.
Her family is holding a private funeral though a public service to celebrate her life and career is expected to be announced.
Peter Warren, Ms MacDonald's office manager at Holyrood and friend, said: "The tributes have been universally good. Even so, I think Margo would have been laughing at some of the words that have been written about her."