Those that
train under Master Roshi, who is also known as Kamesennin or Turtle
Sage, wear his symbol.
Those that
make it through Snake Way and are allowed to train with King Kai
are given this symbol.
Those that
work for the evil alien wear this symbol. 
Symbol worn
by all that are associated with the group. Even the Androids that
are constructed by Dr Gero after the defeat of the group wear
this symbol.
This logo of
Capsule Corporation, is seen worn by Trunks when he makes his
first appearance. He wears the symbol on his jacket and it is
noticed by Bulma.
Symbol standing
for "god". Acquired it when he ascended to the throne
of Earth's protector, he wears it on the front of his clothing.
Gives it up once he merges with Piccolo.
Majiin "M"-
Supopobitchi, Yam, Pai Pai, Yakon, Dabura and Vegeta. Majiin Buu
wears it on his belt. Babidi has it on the front of his belt.
Signifies someone is controlled by Babidi, his slave. Appears
on the forehead.
This red crest
is worn by King Vegeta on his armor. Vegeta wears this crest on
his royal armor but gives it up when his father is killed and
his planet is destroyed.
It looks much
like Frieza's but differs in color and form of his head. 
Symbol Gohan
wears during the Radditz saga. He discards this symbol when he
begins his training with Piccolo.
Piccolo
leaves Gohan to fend for himself in the wilderness as the first
part of his trainning. Gohan is then given a sword and new clothing
by Piccolo. His outfit is similar to his fathers and he wears
Piccolo's symbol on the front.
Symbol worn
on his hat.
Wears this
symbol that stands for "Ox" on his horned hat.
Wears this
symbol on the front of his clothing. 