I linked a Warlockracy video because I really enjoy his choice of games and presentation.
Other channels I really enjoy: Mandalore, Grim Beard, Civvie11, Oboeshoesgames, and Boulder Punch.
If you can’t tell, I like longform, scripted and edited videos on older games and niche games and mods.
Gaming is a pretty broad topic, so I’ll give a range of answers that are gaming related but not necessarily strictly gameplay.
Summoning Salt - Speedrun Historian
8-Bit Music Theory - Video Game Music Theory
Game Maker’s Toolkit - Video Game Design Theory
Jacob Geller - Video Essayist with focus on Games
DougDoug - Community Influenced Gameplay with Light Coding (also hilarious)
But that’s my selection.