B-trees Courses

Data Structures and Algorithm Design Part II | 数据结构与算法设计(下)
Tsinghua University via edX

Hacking PostgreSQL: Data Access Methods
Ural Federal University via edX

Ordered Data Structures
University of Illinois at Urbana-Champaign via Coursera

I/O-efficient algorithms
EIT Digital via Coursera

Data Structures and Algorithms (III)
Tsinghua University via Coursera

Algorithms Data Structures in Java #1 (+INTERVIEW QUESTIONS)
Udemy

Database Engineering
Hussein Nasser via YouTube