we can see the same characteristics used in each different logo with the same similarities:
a)They are a vector based graphics created using illustrator
b)they have bright and bold colour palettes mainly consisting on the same colours such as: red,blue,green,yellow, pink and some with a particial colour of black.
c)Majority of these logos are not accompanied with the company/brand name using on the imagery for the logo.
source:just creative design
alot of the logos use bright colours and use overlapping/linking in to each other or use a symbol shaped in to something as something to remember as a mark.
Some of the designs are simple but still make a statement from their statement whilst others are alot more complex and their detail may not show up well as the simple designs do,
This shows me that when designing logos that the logos designs that work best, are the ones that are kept simple and have a symbol with them to make them more rememberable.