My recommendations

Markdown

• notion
• hedgedoc
• obsidian
• overleaf

Schematics

• Eagle
• LTSpice
• KiCad

Math

• Mathematica
• Matlab
• Octave
• Desmos: simple online plotter

Python

• miniconda

Record your video

• zoom
• OBS studio

Productivity

• anki: flash cards
• habitica: habit tracking
• xmind: mind mapping tool
• cute pomodoro