For some reason i am loving that last sig, the one called "Marvin" although quite plain. The Yoda tag is ok but i don't feel that colour suits Yoda, the colour somewhat symbolizes rage and Yoda is a more peaceful kinda character so green or blue would have been a little better IMO. The other two are ok could be better though, should have taken a little more time with your work IMO as you can clearly do better by the look of your current tag.