Knowledge of the Future of the Universe (10%)
This probably works best for pulp games.
At will, any suitable Mythos entity can impart memories of the future
to a character. The information is instantly learned, but causes a
1d6 Sanity points. Most of the
memories will be suppressed by the character’s feeble human mind
trying to make sense of all this, but particularly strong ones (for
example, faces of key NPCs) will be easily accessible.
Since this is more-or-less a “truthfully answer any plot-relevant question” skill in an investigation game I suggest giving a low skill value, like 10%. You want the character to occasionally have a brilliant flash of foreknowledge which solves their immediate problem, but without trivialising the rest of the campaign.
The character can spend
concentrating to attempt to answer a question about the future. On
failure, the character either doesn’t have, or cannot recall, a
relevant memory. This is not divination, they cannot recall anything
which the giver of the memories did not impart.
Rolls cannot be pushed, and can only have Luck spent on them once per day.
The skill cannot be improved (but more memories could be gifted in the same way).
The GM may give the character a vision, if they encounter something strongly related to a memory.