A common example of a simile for bold is "as bold as brass".
"As bold as the day" is another example. "Bold as a bucket" is another.
It depends on the context of your sentence.
Here are a few more examples:
A bit of boldness will get us past the guard.
"As brave as a lion."
A simile.
Conan the Valiant was created in 1988.
Plymouth Valiant was created in 1960.
Plymouth Valiant ended in 1976.
Sword of the Valiant was created in 1984.
James Valiant died in 1917.
James Valiant was born in 1884.
Valiant Records ended in 1967.
Valiant Records was created in 1960.
Jimmy Valiant is 6' 2".
Johnny Valiant is 6' 1".
Michael Valiant is 5' 9".