Start with a realistic lion picture (to get a standard lion idea).
Nowadays most regular and famous type is the diamond/line made lions.
To get ideas for your own, maybe the best choose will a colored diamond styled (I have never seen before that type)
Upper arm lion tattoo
Bit more artistic upper arm lion
Made by www.tattootemple.hk
Chest Lion tattoo
Made by Elvin Tattoo
Full Chest diamond Lion Tattoo
Diamond styled made by Felipe Kross