To find files by extension (ex: .jpg):
find . -iname "*.jpg"

To find directories:
find . -type d

To find files:
find . -type f

To find files by octal permission:
find . -type f -perm 777

To find files with setuid bit set:
find . -xdev \( -perm -4000 \) -type f -print0 | xargs -0 ls -l