Level Up: Your authentic guide to authentic confidence & internal bliss - James D. Wolfe
The six pillars of self esteem & how to raise your self esteem - Nathaniel Branden
The subtle art of not giving a fuck - Mark Manson
The 7 steps to inner game power - Dan Silverman

Probably got a few more at home that are good also. The first 3 above are all available in kindle format for cheap as chips. Ive got pretty much all David De Angelos stuff I acquired back in his hay day but barely looked at any of it, not sure if it would be out dated now or if I could still punt it on ebay for a decent price.