The chapter Electronic Displacements in a Covalent Bond on curlyarrows.com tries to cover in-depth all the electron-shifting effects that drive chemical reactions. The common ones are Electronegativity, Inductive, Resonance, and Hyperconjugative effects.
CurlyArrows has created a beginner's guide- Introductory Organic Chemistry as a prerequisite to organic chemistry reactions. It comprises 13 carefully crafted, simplified, illustrative, and descriptive chapters.