This has become a resent interest and experiment of mine.
What I have found that works:
Alpha GPC 90m prior; or,
4G L-tyrosine with 400 mg of DMAE (or powerdrive) 60m prior
For concentration/motivation I am using this stack:
500mg CDP Choline
700mg n acetyle tyrosine
200mg l theanine
150mg-300mg caffeine (depending on time of day and sleep)
I've found that the above stack improves my mood as well.
Tried noopept, but it seemed to make me impatient and I think affected my ability to fall asleep. Although, only tried 3x.