nothing legal, however if youre willing to bend the rules a little then there are some options available:
Amphetamines (adderall/vyvanse/amfexa etc): these will easily clear the fog from lack of sleep, the downside being theyre expensive
Modafinil: this chemical was developed for narcolepsy but was soon found to be useful for cognitive enhancement, itll keep you going up to 48 hours with almost no loss of focus or ability and in some cases youll even be better. the other up side to this is that Modafinil is very cheap
Amphetamines (adderall/vyvanse/amfexa etc): these will easily clear the fog from lack of sleep, the downside being theyre expensive
Modafinil: this chemical was developed for narcolepsy but was soon found to be useful for cognitive enhancement, itll keep you going up to 48 hours with almost no loss of focus or ability and in some cases youll even be better. the other up side to this is that Modafinil is very cheap