The Mission by Sam “Moonskinned” Lamont (Portfolio) is featured in Soul Arts on page 242 and Ailing Loran by Thomas Chamberlain-Keen (Instagram, Twitter) on page 214.
They were the joint winners of the Bloodborne art competition so they are both referenced on the slipcover in a combined symbol: The Mission by the depiction of the moon cycle and Ailing Loran by a symbol of a giant tick, the Ixodida queen.
The winners of the other art competitions are referenced by slipcover symbols as well.