This artist's portfolio is all about super clean lines and interesting patterns.
It doesn't get any simpler than a straight line across a thumb.
A morse code tattoo will keep them guessing.
Another tiny finger tattoo by the same artist as above, this time featuring a wee lightning bolt. You could embrace your Harry Potter fandom with that one.
These are to die for.
If you want to find more of these on Instagram, or similar minimalist style tattoos, search for #tinytattoos, #fingertattoos, and #minimaltattoos.