Using numbers as the graphic is interesting and unique, but actually it makes you think about what is the significance. One of the design criteria is that it should not be confusing and make you think too much - so unfortunately I will have to de-select these designs
#192 the use of an exclamation mark seems totally unsuiatble for a certification mark. It seems to be wanting to make some sort of statement, and to portray a professional authoritative viewpoint.
#191 is the only one that works. taking one character . modifying it and adding some colour. a simple approach. you will need to provide a copy with text 'certifiction' to be rated